Question:

How many 50 milligram Tramadol does it take to get high?

Answer:

Do not take extra medicine to get high. Call your doctor if you believe you have taken too many Tramadol.

More Info:

InChI=1S/C18H21NO3/c1-19-8-7-18-11-4-5-13(20)17(18)22-16-14(21-2)6-3-10(15(16)18)9-12(11)19/h3-6,11-13,17,20H,7-9H2,1-2H3/t11-,12+,13-,17-,18-/m0/s1Yes 
Key:OROGSEYTTFOCAN-DNJOTXNNSA-NYes  Codeine or 3-methylmorphine (a natural isomer of methylated morphine) is an opiate used for its analgesic, antitussive, antidiarrheal, antihypertensive, anxiolytic, antidepressant, sedative and hypnotic properties. It is also used to suppress premature labor contractions, myocardial infarction, and has many other potential and indicated uses. Codeine is the second-most predominant alkaloid in opium, at up to three percent. Although codeine can be extracted from natural sources, a semi-synthetic process is the primary source of codeine for pharmaceutical use. It is considered the prototype of the weak to midrange opioids (tramadol, dextropropoxyphene, dihydrocodeine, hydrocodone, oxycodone). Codeine is used to treat mild to moderate pain and to relieve cough. Codeine is also used to treat diarrhea and diarrhea predominant irritable bowel syndrome, although loperamide (which is available OTC for milder diarrhea), diphenoxylate, paregoric or even laudanum (also known as Tincture of Opium) are more frequently used to treat severe diarrhea. Codeine is marketed as both a single-ingredient drug and in combination preparations with paracetamol (as co-codamol: e.g., brands Paracod, Panadeine. Paramol, and the Tylenol-with-codeine series, including Tylenol 3 and 1,2,4); with aspirin; (as co-codaprin); or with ibuprofen (as Nurofen Plus). These combinations provide greater pain relief than either agent alone (drug synergy). Codeine is also commonly marketed in products containing codeine with other pain killers or muscle relaxers, as well as codeine mixed with phenacetin (Emprazil With Codeine No. 1, 2, 3, 4 and 5), naproxen, indomethacin, diclofenac, and others, as well as more complex mixtures, including such mixtures as aspirin + paracetamol + codeine ± caffeine ± antihistamines and other agents, such as those mentioned above. Codeine-only products can be obtained with a prescription as a time release tablet (e.g., Codeine Contin 100 mg and Perduretas 50 mg). Codeine is also marketed in cough syrups with zero to a half-dozen other active ingredients, and a linctus (e.g., Paveral) for all of the uses for which codeine is indicated. Injectable codeine is available for subcutaneous or intramuscular injection; intravenous injection can cause a serious reaction that can progress to anaphylaxis. Codeine suppositories are also marketed in some countries. Common adverse effects associated with the use of codeine include drowsiness and constipation. Less common are euphoria, itching, nausea, vomiting, dry mouth, miosis, orthostatic hypotension, urinary retention, depression, and, paradoxically, coughing. Rare adverse effects include anaphylaxis, seizure, and respiratory depression. As with all opiates, longer-term effects can vary but can include diminished libido, apathy and memory loss. Some people may also have an allergic reaction to codeine, such as the swelling of skin and rashes. Codeine and morphine as well as opium were used for control of diabetes until relatively recently, and still are in rare cases in some countries, and the hypoglycemic effect of codeine, although usually weaker than that of morphine, diamorphine, or hydromorphone, can lead to cravings for sugar. Tolerance to many of the effects of codeine develops with prolonged use, including therapeutic effects. The rate at which this occurs develops at different rates for different effects, with tolerance to the constipation-inducing effects developing particularly slowly for instance. A potentially serious adverse drug reaction, as with other opioids, is respiratory depression. This depression is dose-related and is the mechanism for the potentially fatal consequences of overdose. As codeine is metabolized to morphine, morphine can be passed through breast milk in potentially lethal amounts, fatally depressing the respiration of a breastfed baby. In August 2012, the Federal Drug Administration issued a warning about deaths in pediatric patients < 6 years old after ingesting "normal" doses of acetaminophen with codeine after tonsillectomy. Some patients are very effective converters of codeine to its active form, hydromorphone, resulting in lethal blood levels. The FDA presently is recommending very cautious use of Codeine in young tonsillectomy patients: use the drug in the lowest amount that can control the pain, use "as needed" and not "around the clock", and seek immediate medical attention if a child on codeine exhibits excessive sedation or abnormally noisy breathing. As with other opiate-based pain killers, chronic use of codeine can cause physical dependence. When physical dependence has developed, withdrawal symptoms may occur if a person suddenly stops the medication. Withdrawal symptoms include: drug craving, runny nose, yawning, sweating, insomnia, weakness, stomach cramps, nausea, vomiting, diarrhea, muscle spasms, chills, irritability, and pain. To minimize withdrawal symptoms, long-term users should gradually reduce their codeine medication under the supervision of a healthcare professional. Codeine is metabolized to codeine-6-glucuronide (C6G) by uridine diphosphate glucuronosyl transferase UGT2B7, and, since only about 5% of codeine is metabolized by cytochrome P450 CYP2D6, the current evidence is that C6G is the primary active compound. Claims about the supposed "ceiling effect" of codeine doses are based on the assumption that high doses of codeine saturate CYP2D6, preventing further conversion of codeine to morphine, however it is now known that C6G is the main metabolite responsible for codeine's analgesia. There is also no evidence that CYP2D6 inhibition is useful in treating codeine dependence, though the metabolism of codeine to morphine (and hence further metabolism to glucuronide morphine conjugates) does have an effect on the abuse potential of codeine. However, CYP2D6 has been implicated in the toxicity and death of neonates when codeine is administered to lactating mothers, particularly those with increased 2D6 activity ("ultra-rapid" metabolizers). The conversion of codeine to morphine occurs in the liver and is catalysed by the cytochrome P450 enzyme CYP2D6. CYP3A4 produces norcodeine and UGT2B7 conjugates codeine, norcodeine, and morphine to the corresponding 3- and 6- glucuronides. Srinivasan, Wielbo and Tebbett speculate that codeine-6-glucuronide is responsible for a large percentage of the analgesia of codeine, and, thus, these patients should experience some analgesia. Many of the adverse effects will still be experienced in poor metabolizers. Conversely, 0.5-2% of the population are "extensive metabolizers"; multiple copies of the gene for 2D6 produce high levels of CYP2D6 and will metabolize drugs through that pathway more quickly than others. Some medications are CYP2D6 inhibitors and reduce or even completely block the conversion of codeine to morphine. The most well-known of these are two of the selective serotonin reuptake inhibitors, paroxetine (Paxil) and fluoxetine (Prozac) as well as the antihistamine diphenhydramine and the antidepressant, bupropion (Wellbutrin, also known as Zyban). Other drugs, such as rifampicin and dexamethasone, induce CYP450 isozymes and thus increase the conversion rate. CYP2D6 converts codeine into morphine, which then undergoes glucuronidation. Life-threatening intoxication, including respiratory depression requiring intubation, can develop over a matter of days in patients who have multiple functional alleles of CYP2D6, resulting in ultra-rapid metabolism of opioids such as codeine into morphine. Studies on codeine's analgesic effect are consistent with the idea that metabolism by CYP2D6 to morphine is important, but some studies show no major differences between those who are poor metabolizers and extensive metabolizers. Evidence supporting the hypothesis that ultrarapid metabolizers may get greater analgesia from codeine due to increased morphine formation is limited to case reports.
The active metabolites of codeine, notably morphine, exert their effects by binding to and activating the μ-opioid receptor. Codeine has been used in the past as the starting material and prototype of a large class of mainly mild to moderately strong opioids; such as hydrocodone (1920 in Germany), oxycodone (1916 in Germany), dihydrocodeine (1908 in Germany), and its derivatives such as nicocodeine (1956 in Austria).][ However, these opiates are no longer synthesized from codeine and are usually synthesized from other opioid alkaloids; specifically thebaine.][ Other series of codeine derivatives include isocodeine and its derivatives, which were developed in Germany starting around 1920. As an analgesic, codeine compares moderately to other opiates. Related to codeine in other ways are codoxime, thebacon, -oxideNcodeine- (genocodeine), related to the nitrogen morphine derivatives as is codeine methobromide, and heterocodeine, which is a drug six times stronger than morphine and 72 times stronger than codeine due to a small re-arrangement of the molecule, viz. moving the methyl group from the 3 to the 6 position on the morphine carbon skeleton. Drugs bearing resemblance to codeine in effects due to close structural relationship are variations on the methyl groups at the 3 position including ethylmorphine a.k.a. codethyline (Dionine) and benzylmorphine (Peronine). While having no narcotic effects of its own, the important opioid precursor thebaine differs from codeine only slightly in structure. Pseudocodeine and some other similar alkaloids not currently used in medicine are found in trace amounts in opium as well. Codeine, or 3-methylmorphine, is an alkaloid found in the opium poppy, Papaver somniferum var. album, a plant in the papaveraceae family. Opium poppy has been cultivated and utilized throughout human history for a variety of medicinal (analgesic, anti-tussive and anti-diarrheal) and hypnotic properties linked to the diversity of its active components, which include morphine, codeine and papaverine. Codeine is found in concentrations of 10 to 3.0 per cent in opium prepared by the latex method from unripe pods of Papaver somniferum. The name codeine is derived from the Greek word kodeia (κώδεια) for "poppy head". The relative proportion of codeine to morphine, the most common opium alkaloid at 4 to 23 per cent, tends to be somewhat higher in the poppy straw method of preparing opium alkaloids. Until the beginning of the 19th century, raw opium was used in diverse preparations known as laudanum (see Thomas de Quincey's "Confessions of an English Opium-Eater", 1821) and paregoric elixirs, a number of which were popular in England since the beginning of the 18th century; the original preparation seems to have been elaborated in Leiden, the Netherlands around 1715 by a chemist named Lemort; in 1721 the London Pharmocopeia mentions an Elixir Asthmaticum, replaced by the term Elixir Paregoricum ("pain soother") in 1746. The progressive isolation of opium's several active components opened the path to improved selectivity and safety of the opiates-based pharmacopeia. Morphine had already been isolated in Germany by German pharmacist Friedrich Sertürner in 1804. Codeine was first isolated decades later in 1832 in France by Pierre Robiquet, a French chemist and pharmacist already famous for the discovery of alizarin, the most widespread red dye, while working on refined morphine extraction processes. This paved the way for the elaboration of a new generation of safer, codeine-based specific antitussive and antidiarrheal formulations. Codeine is currently the most widely-used opiate in the world, and is one of the most commonly used drugs overall according to numerous reports by organizations including the World Health Organization and its League of Nations predecessor agency. It is one of the most effective orally administered opioid analgesics and has a wide safety margin. Its strength ranges from 8 to 12 percent of morphine in most people; differences in metabolism can change this figure as can other medications, depending on its route of administration. While codeine can be directly extracted from opium, its original source, most codeine is synthesized from the much more abundant morphine through the process of O-methylation. By 1972, the effects of the Nixon War On Drugs had caused across-the-board shortages of illicit and licit opiates because of a scarcity of natural opium, poppy straw, and other sources of opium alkaloids, and the geopolitical situation was growing difficult for the United States. After a large percentage of the opium and morphine in the US National Stockpile of Strategic & Critical Materials was tapped in order to ease severe shortages of medicinal opiates — the codeine-based antitussives in particular — in late 1973, researchers were tasked with finding a way to synthesize codeine and its derivatives. They quickly succeeded using petroleum or coal tar and a process developed at the United States' National Institutes of Health. Numerous codeine salts have been prepared since the drug was discovered. The most commonly used are the hydrochloride (freebase conversion ratio 0.805), phosphate (0.736), sulphate (0.859), and citrate (0.842). Others include a salicylate NSAID, codeine salicylate (0.686), and at least four codeine-based barbiturates, the cyclohexenylethylbarbiturate (0.559), cyclopentenylallylbarbiturate (0.561), diallylbarbiturate (0.561), and diethylbarbiturate (0.619). Codeine can be used as a recreational drug. In some countries, cough syrups and tablets containing codeine are available without prescription; some potential recreational users are reported to buy codeine from multiple pharmacies so as not to arouse suspicion. In countries like Canada, in an effort to reduce recreational use, all OTC purchases of codeine are electronically recorded, and any pharmacy can access these records if desired. A heroin addict may use codeine to ward off the effects of a withdrawal. Codeine is also available in conjunction with the anti-nausea medication promethazine in the form of a syrup. Brand named as Phenergan with Codeine or in generic form as promethazine with codeine. Called 'syrup', this medication is quickly becoming one of the most commonly misused codeine preparations. Rapper Pimp C, from the group UGK, died from an overdose of this combination. Codeine is also demethylated by reaction with pyridine to illicitly synthesize morphine, which can then be acetylated to make heroin (diacetylmorphine). Pyridine is toxic and possibly carcinogenic, so morphine illicitly produced in this manner (and potentially contaminated with pyridine) may be particularly harmful. Codeine can also be turned into α-chlorocodide, which is used in the clandestine synthesis of desomorphine (Permonid) (desomorphine attracted attention in 2010 in Russia due to an upsurge in clandestine production, presumably due to its relatively simple synthesis from codeine.][ The drug is easily made from codeine, iodine and red phosphorus, in a similar process to the manufacture of methamphetamine from pseudoephedrine, but desomorphine made this way is highly impure and contaminated with various toxic and corrosive byproducts.). Codeine and/or its major metabolites may be quantitated in blood, plasma or urine to monitor therapy, confirm a diagnosis of poisoning or assist in a medicolegal death investigation. Drug abuse screening programs generally test urine, hair, sweat or oral fluid. Many commercial opiate screening tests directed at morphine cross-react appreciably with codeine and its metabolites, but chromatographic techniques can easily distinguish codeine from other opiates and opioids. It is important to note that codeine usage results in significant amounts of morphine as an excretion product. Furthermore, heroin contains codeine (or acetylcodeine) as an impurity and its use will result in excretion of small amounts of codeine. Poppy seed foods represent yet another source of low levels of codeine in one's biofluids. Blood or plasma codeine concentrations are typically in the 50–300 µg/L range in persons taking the drug therapeutically, 700–7000 µg/L in chronic users and 1000–10,000 µg/L in cases of acute fatal overdosage. In Australia, Canada, New Zealand, Romania, Russia, Sweden, the United Kingdom, the United States, and many other countries, codeine is regulated under various narcotic control laws. In some countries it is available without prescription in combination preparations from licensed pharmacists in doses up to 15 mg/tablet in Australia, New Zealand, Poland, Romania (Codamin), and Costa Rica, 12.8 mg/tablet in the UK, 10 mg/tablet in Israel and 8 mg/tablet in Canada and Estonia.][ In Australia, codeine preparations must be sold only at a pharmacy. Preparations will often be a combination of paracetamol (500 mg), ibuprofen (200 mg) and doxylamine succinate (5 mg), and the codeine content may range from 5 mg to 15 mg; preparations with in excess of 30 mg per tablet are S4 (schedule 4, or Prescription Only) medications. The item is given over the counter, no prescriptions, at the discretion of the Pharmacist. Most preparations are considered S3 (schedule 3, or Pharmacist Only) medications, meaning that they must be sold with the direct involvement of a pharmacist. It must be labelled and usage history monitored by the Pharmacist to help deter misuse and dependence. The exception to this rule is cold and flu preparations such as "Codral". These preparations contain phenylephrine (5 mg), paracetamol(500 mg) and codeine(9.5 mg).
Preparations containing pure codeine (e.g., codeine phosphate tablets or codeine phosphate linctus) are available on prescription and are considered S8 (schedule 8, or Controlled Drug (Possession without authority illegal)). Schedule 8 preparations are subject to the strictest regulation of all medications available to consumers. In Denmark codeine is sold over the counter with max 9.6 mg in mixture.][ The item is given over the counter, no prescriptions. The strongest available over the counter preparation containing codeine has 9.6 mg (with aspirin, brand name Kodimagnyl); anything stronger requires a prescription. In France, most preparations containing codeine do not require a doctor's prescription. Example products containing codeine include Néocodion (cough pills, ad sirup), Codoliprane (codeine with paracetamol), Prontalgine and Migralgine (codeine, paracetamol and caffeine). Codeine is listed under the Betäubungsmittelgesetz in Germany and the similarly named narcotics and controlled substances law in Switzerland. In Austria, the drug is listed under the Suchtmittelgesetz in categories corresponding to their classification under the Single Convention on Narcotic Drugs. Dispensing of products containing codeine and similar drugs (dihydrocodeine, nicocodeine, benzylmorphine, ethylmorphine etc.), in general, requires a prescription order from a doctor or the discretion of the pharmacist. Municipal and provincial regulations may impact availability, in particular in Austria and Switzerland, which allows cities and provinces to regulate the selling of the least-regulated schedule of the SMG/BtMG; and, of course, individual chemists' shops can opt out of providing them or imposing volume, frequency, or single-purchase limitations and other things of the same store. Plain codeine hydrochloride tablets (which in the USA would share CSA Schedule II with drugs like morphine, cocaine, hydromorphone, and bezitramide) as well as other non-injectable forms of codeine and its midrange derivatives can be dispensed in this way; the same goes for most chemical classes of benzodiazepines, the majority of non-barbiturate sedative/hypnotics, and at least a handful of barbiturates. Title 76 of the Schengen treaty has made it possible for countries within the signatory states to import and export drugs with various provisos, recording and ordering requirements, and various other rules. Codeine is classed as an illegal drug in Greece, and individuals possessing it could conceivably be arrested, even if they were legitimately prescribed it in another country. It is sold only with a doctor's prescription (Lonarid-N, Lonalgal). In Hong Kong, codeine is regulated under Schedule 1 of Hong Kong's Chapter 134 Dangerous Drugs Ordinance. It can be used legally only by health professionals and for university research purposes. The substance can be given by pharmacists under a prescription. Anyone who supplies the substance without prescription can be fined $10,000 (HKD). The maximum penalty for trafficking or manufacturing the substance is a $5,000,000 (HKD) fine and life imprisonment. Possession of the substance for consumption without license from the Department of Health is illegal with a $1,000,000 (HKD) fine and/or 7 years of jail time. However, codeine is available without prescription from licensed pharmacists in doses up to 0.1% (5 mg/5ml) according to Hong Kong "Dangerous Drugs Ordinance". Preparations of paracetamol and codeine require a prescription in Iceland. These tablets are known as Parkódín. Codeine preparations require a prescription in India. A preparation of paracetamol and codeine is available in India. Codeine is also present in various cough syrups as Codeine Phosphate. In the Republic of Ireland, new regulations came into effect on August 1, 2010 concerning codeine, due to worries about the overuse of the drug. Codeine remains a semi non-prescriptive, over-the-counter drug up to a limit of 12.8 mg per pill, but codeine products must be out of the view of the public to facilitate the legislative requirement that these products “are not accessible to the public for self-selection”. In practice, this means customers must ask pharmacists for the product containing codeine in name, and the pharmacist makes a judgement whether it is suitable for the patient to be using codeine, and that patients are fully advised of the correct use of these products. Products containing more than 12.8 mg codeine are available on prescription only. Codeine tablets or preparations require a prescription in Italy. A preparation of paracetamol and codeine is available in Italy as Co-Efferalgan. Codeine and similar mid-level centrally acting agents in combination with non-opioid analgesics, antihistamines, vitamins, inert GI agents like kaolin & pectin, mild laxatives, antacids, and herbal preparations, can be purchased over the counter, with 10 mg being the ceiling for OTC dispensing. This is also true of ethylmorphine and dihydrocodeine, and also diphenoxylate, some weak relatives of the thiambutene opioid family. According to ITAR-Tass and Austria Presse-Agentur, OTC availability of codeine products was rescinded nationwide in 2012 because of the discovery of the Krokodil method of underground desomorphine synthesis. Opponents of the move point out that codeine has not been available OTC in 22 of Russia's oblasts for years and the demand will call forth its own supply, meaning that only legitimate end users are negatively impacted (activist quoted in Pravda story on issue) Codeine preparations are available as over the counter pharmacy medicines in Sri Lanka. The most common preparation is Panadeine, which contains 500 mg of Paracetamol and 8 mg of Codeine. Narcotic content number in the US names of codeine tablets and combination products like Tylenol With Codeine No. 3, Emprin With Codeine No. 4, and pure codeine tablets are as follows: No. 1 - 7½ or 8 mg (1/8 grain), No. 2 - 15 or 16 mg (1/4 grain), No. 3 - 30 or 32 mg (1/2 grain), No. 4 - 60 or 64 mg (1 grain). The Canadian "Frosst 222" series is identical to the above list: "222" contains 8 mg codeine, "282" 15 mg, "292" 30 mg, and "293" 60 mg. This system, which is also used at present in the trade names of some dihydrocodeine and ethylmorphine products both in and outside of North America, was inaugurated with the Pure Food and Drug Act of 1906 and related legislation and refined since. Equivalent scales for labeling stronger opioids such as diacetylmorphine (heroin), morphine, opium salts mixtures, and others were in common use in the past, and on occasion one can find past references to brand names for hydrocodone (invented 1920, introduced in US 1943), hydromorphone (invented 1924), oxycodone (invented 1916), paregoric and similar drugs containing narcotic content numbers. For example. from circa 1900 to 1925, the most common cough medicine was terpin hydrate With Heroin Elixir No. 2. Contrary to the advertising matter of some pharmacies, 60 mg is No. 4, not No. 6, and tablets with 45 mg of codeine are not No. 4 and would in all likelihood be classified as No. 3½ under that system. Whether the scale goes to No. 5 and higher is moot at this point, as in the United States and Canada single-dose-unit concentrations of more than 64 mg are not manufactured. The United States Controlled Substances Act of 1970 does place dosage unit strengths of 90 mg of codeine and higher in Schedule II, even if mixed with another active ingredient. Oral tablets, hypodermic tablets, liquid forms, and capsules of less common doses are available in some cases the equivalent dihydrocodeine, dionine, benzylmorphine, and opium dosages were previously available in North America (and in most cases still are in other countries, particularly the 45 mg paracetamol/codeine and 50 and 100 mg single-ingredient codeine tablets). In the United States, codeine is regulated by the Controlled Substances Act. Federal law dictates that codeine be a Schedule II controlled substance when used in products for pain-relief that contain codeine alone or more than 90 mg per dosage unit. Tablets of codeine in combination with aspirin or acetaminophen (paracetamol/Tylenol) made for pain relief are listed as Schedule III; and cough syrups are Schedule III or V, depending on formula. The acetaminophen/codeine pain-relief elixir (trade name Tylenol Elixir with Codeine) is a Schedule IV controlled substance. Some states, however, have chosen to classify Schedule V codeine preparations into a more restrictive schedule in order to cut down the abuse of prescription codeine preparations. Minnesota, for instance, has chosen to reclassify Schedule V codeine preparations (such as Cheratussin) as a Schedule II controlled substance. Preparations for cough or diarrhea containing small amounts of codeine in combination with two or more other active ingredients are Schedule V in the US, and in some states may be dispensed in amounts up to 4 fl. oz. per 48 hours (one or two states set the limit at 4 fl. oz. per 72 hours) without a prescription. Schedule V specifically consigns the product to state and local regulation beyond certain required record-keeping requirements (a dispensary log must be maintained for two years in a ledger from which pages cannot easily be removed and/or are pre-numbered, and the pharmacist must ask for photo identification) and also maintain controlled substances in the closed system at the root of the régime intended by the Controlled Substances Act of 1970; the codeine in these products was a Schedule II substance when the company making the Schedule V product acquired it for mixing up the end-product. In locales where dilute codeine preparations are non-prescription, anywhere from very few to perhaps a moderate percentage of pharmacists will sell these preparations without a prescription. However, many states have their own laws that do require a prescription for Schedule V drugs. The December 2008 issue of The Bulletin of the National Codeine OTC Lobby (Vol. XVIII, No. 4) listed 12 states with some kind of OTC access to codeine, noting that small independent pharmacies are the most likely to have it. This situation is roughly equivalent to that in February 1991, when the aforementioned organisation undertook its first comprehensive study of Schedule V and overall codeine, dihydrocodeine, ethylmorphine, and hydrocodone availability. Other drugs that are present in Schedule V narcotic preparations like the codeine syrups are ethylmorphine and dihydrocodeine. Paregoric and hydrocodone were transferred to Schedule III from Schedule V even if the preparation contains two or more other active ingredients, and diphenoxylate is usually covered by state prescription laws even though this relative of pethidine is a Schedule V substance when adulterated with atropine to prevent abuse. Around the world, codeine is, contingent on its concentration, a Schedule II and III drug under the Single Convention on Narcotic Drugs. Codeine tablets or preparations require a prescription in Spain, although this is often not enforced and many pharmacies will sell codeine products without the requirement of a prescription.][ The UAE takes an infamously strict line on medicines, with many common drugs, notably anything with containing codeine being banned unless you have a notarized and authenticated doctor's prescription. Visitors breaking the rules, even inadvertently, have found themselves deported or jailed. The US Embassy to the UAE maintains an unofficial list of what may not be imported. In the United Kingdom, neat codeine and higher-strength codeine formulations - such as 30/500 co-codamol (where 30 mg of codeine phosphate is combined with 500 mg paracetamol) are prescription-only medicines (POM). Lower-strength combinations, such as 8/500 (various brands) or 12.8/500 (Panadol Ultra, Solpadeine MAX and others) are available as pharmacy medicines over the counter. Codeine is also available combined with Ibuprofen; a common formulation is 12.8 mg codeine alongside 200 mg Ibuprofen. It is also available 'behind the counter' with aspirin in doses of 8 mg codeine phosphate and 500 mg aspirin (Codis). Codeine Linctus of 15 mg per 5ml is also available behind the counter at some pharmacies, although a purchaser would have to request it specifically from the pharmacist. Under the Misuse of Drugs Act 1971, possession of codeine is legal without a prescription in quantities of up to 12.5 mg when in tablet form. As with most opioids, possession of neat codeine without a prescripion is illegal in quantities over 12.5 mg and is currently a class B controlled drug. However, if it prepared for intra-muscular injection, it is then considered to be a class A controlled drug. Thus it is legal for a person to carry neat codeine in quantities over 12.5 mg assuming that they possess a valid prescription, subject to the quantities carried being for personal use only and with no indication that there is intent to supply. M: CNS anat (n/s/m/p/4/e/b/d/c/a/f/l/g)/phys/devp noco (m/d/e/h/v/s)/cong/tumr, sysi/epon, injr proc, drug (N1A/2AB/C/3/4/7A/B/C/D) M: DIG anat (t, g, p)/phys/devp/enzy noco/cong/tumr, sysi/epon proc, drug (A2A/2B/3/4/5/6/7/14/16), blte M: RES anat (n, x, l, c)/phys/devp noco (c, p)/cong/tumr, sysi/epon, injr proc, drug (R1/2/3/5/6/7)
InChI=1S/C15H23NO2/c1-16(2)11-13-6-3-4-9-15(13,18)12-7-5-8-14(17)10-12/h5,7-8,10,13,17-18H,3-4,6,9,11H2,1-2H3Yes 
Key:UWJUQVWARXYRCG-UHFFFAOYSA-NYes  O-Desmethyltramadol (O-DT) is an opioid analgesic and the main active metabolite of tramadol. (+)-O-Desmethyltramadol is the most important metabolite of tramadol produced in the liver after tramadol is consumed. This metabolite is considerably more potent as a μ opioid agonist than the parent compound. Tramadol is demethylated by the liver enzyme CYP2D6 in the same way as codeine, and so similarly to the variation in effects seen with codeine, individuals who have a less active form of CYP2D6 ("poor metabolisers") will tend to get reduced analgesic effects from tramadol.][ The two enantiomers of O-desmethyltramadol show quite distinct pharmacological profiles; both (+) and (−)-O-desmethyltramadol are inactive as serotonin reuptake inhibitors, but (−)-O-desmethyltramadol retains activity as a noradrenaline reuptake inhibitor and so the mix of both the parent compound and metabolites produced contributes significantly to the complex pharmacological profile of tramadol. O-Desmethyltramadol has recently been marketed as a currently legal substitute for illegal opioid drugs, either in powder form or mixed into various other preparations. One such blend sold under the brand Krypton and containing powdered kratom leaf (Mitragyna speciosa) laced with O-desmethyltramadol was reportedly linked to at least 9 accidental deaths from overdose during 2010–2011. The opioid medication tapentadol was developed to mimic the actions of O-desmethyltramadol in order to create a weak-moderate analgesic which is not dependent on metabolic activation. O-Desmethyltramadol is metabolized in the liver into the active metabolite N,O-didesmethyltramadol via CYP2D6. The inactive tramadol metabolite N-desmethyltramadol is also metabolized into the active metabolite N,O-didesmethyltramadol by the same enzyme.
InChI=1S/C16H25NO2/c1-17(2)12-14-7-4-5-10-16(14,18)13-8-6-9-15(11-13)19-3/h6,8-9,11,14,18H,4-5,7,10,12H2,1-3H3/t14-,16+/m1/s1Yes 
Key:TVYLLZQTGLZFBW-ZBFHGGJFSA-NYes  Tramadol hydrochloride (trademarked as Conzip, Rybix, Ryzolt, Ultracet, Ultram in the USA, Ralivia, Zytram XL Durella{CR-100/200 mg} in Canada or Adolonta in Spain) is a centrally acting synthetic opioid analgesic used to treat moderate to moderately severe pain. The drug has a wide range of applications, including treatment of rheumatoid arthritis, restless legs syndrome, motor neurone disease and fibromyalgia.][ It was launched and marketed as Tramal by the German pharmaceutical company Grünenthal GmbH in 1977. Tramadol is a weak μ-opioid receptor agonist, a serotonin releaser and a reuptake inhibitor of norepinephrine. Tramadol is metabolized to -desmethyltramadolO, a significantly more potent μ-opioid agonist. Tramadol and its major metabolite(s) are distinguished from other more potent opioid agonists by relative selectivity for μ-opioid receptors. Tramadol is used similarly to codeine, to treat moderate to severe pain. Pharmacologically, Tramadol is similar to levorphanol (albeit with much lower μ-agonism), both agents have SNRI activity. Dextropropoxyphene (Darvon) & M1-like molecule tapentadol (Nucynta, a new synthetic atypical opioid made to mimic the agonistic properties of tramadol's metabolite, M1(O-Desmethyltramadol)) also have similar activities. Tramadol is also molecularly similar to venlafaxine (Effexor) and has similar SNRI effects, with antinociceptive effects. It has been suggested that tramadol could be effective for alleviating symptoms of depression, anxiety, and phobias because of its action on the noradrenergic and serotonergic systems, such as its "atypical" opioid activity. However, health professionals have not endorsed its use for these disorders, claiming it may be used as a unique treatment (only when other treatments failed), and must be used under the control of a psychiatrist. In May 2009, the United States Food and Drug Administration issued a Warning Letter to Johnson & Johnson, alleging that a promotional website commissioned by the manufacturer had "overstated the efficacy" of the drug, and "minimized the serious risks". The company which produced it, the German pharmaceutical company Grünenthal GmbH, were alleged to be guilty of "minimizing" the habituating nature of the drug, although it showed little abuse liability in preliminary tests.][ The 2010 Physicians' Desk Reference contains several warnings from the manufacturer, which were not present in prior years. The warnings include stronger language regarding the habituating potential of tramadol, the possibility of difficulty breathing while on the medication, a new list of more serious side effects, and a notice that tramadol is not to be used in place of opiate medications for addicts. Tramadol is also not to be used in efforts to wean addict patients from opiate drugs, nor to be used to manage long-term opiate addiction. Tramadol is classified as a central nervous system drug usually marketed as the hydrochloride salt (tramadol hydrochloride); the tartrate is seen on rare occasions, and rarely (in the US at least) tramadol is available for both injection (intravenous and/or intramuscular) and oral administration. The most well known dosing unit is the 50 mg generic tablet made by several manufacturers. It is also commonly available in conjunction with APAP (paracetamol, acetaminophen) as Ultracet or Tramacet, in the form of a smaller dose of 37.5 mg tramadol and 325 mg of APAP. Tramadol is not a federally controlled drug, however the following U.S. states have elected to make tramadol a schedule IV controlled drug: Arkansas, Tennessee, Illinois, New Mexico, New York, Ohio, West Virginia, Kentucky, Wyoming, Mississippi, North Dakota, Oklahoma and the U.S. military, with other states considering similar actions. Tramadol comes in many forms, including: Tramadol is regularly used in the form of an ingredient in multi-agent topical gels, creams, and solutions for nerve pain, rectal foam, concentrated retention enema, and a skin plaster (transdermal patch) quite similar to those used with lidocaine. Tramadol has a characteristic and unpleasant taste which is mildly bitter but much less so than morphine and codeine. Oral and sublingual drops and liquid preparations come with and without added flavoring. This different flavouring is considered to be a standard. Its relative effectiveness via transmucosal routes (i.e. sublingual, buccal, rectal) is similar to that of codeine, and, like codeine, it is also metabolized in the liver to stronger metabolites (see below). Patients taking SSRIs (Prozac, Zoloft, etc.), SNRIs (Effexor, etc.), TCAs, MAOIs or other strong opioids (oxycodone, methadone, fentanyl, morphine), as well as the elderly (> 75 years old), pediatric (< 18 years old), and those with severely reduced renal (kidney) or hepatic (liver) function should consult their doctor regarding adjusted dosing or whether to use tramadol at all. The most commonly reported adverse drug reactions are nausea, vomiting, sweating, itching and constipation. Drowsiness is reported, although it is less of an issue than for other opioids.][ Patients prescribed tramadol for general pain relief with or without other agents have reported withdrawal symptoms including uncontrollable nervous tremors, muscle contracture, and 'thrashing' in bed (similar to restless leg syndrome) if weaned off the medication too quickly. Anxiety, 'buzzing', 'electrical shock' and other sensations may also be present, similar to those noted in Effexor withdrawal. It can also produce delayed ejaculation and other sexual dysfunctions, mainly due to its interaction with 5HT. Respiratory depression, a common side-effect of most opioids, is not clinically significant in normal doses. By itself, it can decrease the seizure threshold. When combined with SSRIs, tricyclic antidepressants, or in patients with epilepsy, the seizure threshold is further decreased. Seizures have been reported in humans receiving excessive single oral doses (700 mg) or large intravenous doses (300 mg). However, there have been several rare cases of people having grand-mal seizures at doses as low as 100–400 mg orally. An Australian study found that of 97 confirmed new-onset seizures, eight were associated with tramadol, and that in the authors' First Seizure Clinic, "tramadol is the most frequently suspected cause of provoked seizures". There appears to be growing evidence that tramadol use may have serious risks in some individuals and it is contra-indicated in patients with uncontrolled epilepsy (BNF 59). Seizures caused by tramadol are most often tonic-clonic seizures, more commonly known in the past as grand mal seizures. Also when taken with SSRIs, there is an increased risk of serotonin toxicity, which can be fatal. Fewer than 1% of users have a presumed incident seizure claim after their first tramadol prescription. Risk of seizure claim increases two- to six-fold among users adjusted for selected comorbidities and concomitant drugs. Risk of seizure is highest among those aged 25–54 years, those with more than four tramadol prescriptions, and those with a history of alcohol abuse, stroke, or head injury. Dosages of warfarin may need to be reduced for anticoagulated patients to avoid bleeding complications. Constipation can be severe especially in the elderly requiring manual evacuation of the bowel.][ Furthermore, there are suggestions that chronic opioid administration may induce a state of immune tolerance, although tramadol, in contrast to typical opioids may enhance immune function. Some have also stressed the negative effects of opioids on cognitive functioning and personality. Long-term use of high doses of Tramadol may be associated with physical dependence and a withdrawal syndrome. Tramadol causes typical opiate-like withdrawal symptoms as well as atypical withdrawal symptoms including seizures][. The atypical withdrawal symptoms are probably related to tramadol's effect on serotonin and norepinephrine re-uptake. Symptoms may include those of SSRI discontinuation syndrome, such as anxiety, depression, anguish, severe mood swings, aggressiveness, brain "zaps", electric-shock-like sensations throughout the body, paresthesias, sweating, palpitations, restless legs syndrome, sneezing, insomnia, vivid dreams or nightmares, micropsia and/or macropsia, tremors, and headache among others. In most cases, tramadol withdrawal will set in 12–20 hours after the last dose, but this can vary. Tramadol withdrawal lasts longer than that of other opioids; seven days or more of acute withdrawal symptoms can occur as opposed to typically three or four days for other codeine analogues. It is recommended that patients physically dependent on pain killers take their medication regularly to prevent onset of withdrawal symptoms and this is particularly relevant to tramadol because of its SSRI and SNRI properties, and, when the time comes to discontinue their tramadol, to do so gradually over a period of time that will vary according to the individual patient and dose and length of time on the drug. Some controversy regarding the abuse potential of tramadol exists. Grünenthal has promoted it as having a lower risk of opioid dependence than traditional opioids, claiming little evidence of such dependence in clinical trials (which is true; Grünenthal never claimed it to be non-addictive). They offer the theory that, since the M1 metabolite is the principal agonist at μ-opioid receptors, the delayed agonist activity reduces abuse liability. The norepinephrine reuptake inhibitor effects may also play a role in reducing dependence. Rarely, dependence may occur after as little as three months of use at the maximum dose—generally depicted at 400 mg per day. However, both physicians and health authorities generally consider dependence liability relatively low. Thus, tramadol is classified as a Schedule 4 Prescription Only Medicine in Australia, and been rescheduled in Sweden rather than as a Schedule 8 Controlled Drug like opioids. Similarly, unlike opioid analgesics, tramadol is not currently scheduled as a controlled substance by the U.S. Drug Enforcement Administration. However, it is scheduled in certain states. Nevertheless, the prescribing information for Ultram warns that tramadol "may induce psychological and physical dependence of the morphine-type". Because of the possibility of convulsions at high doses for some users, recreational use can be very dangerous. Tramadol can cause a higher incidence of nausea, dizziness, loss of appetite compared with opiates, which could deter abuse. Compared to hydrocodone, fewer patients choose to abuse Tramadol. It may also have a large effect on sleeping patterns and high doses may cause insomnia. (Especially for those on methadone, both for maintenance and recreation. Though there is no scientific proof tramadol lessens effects of opiates or is a mixed agonist-antagonist, some people get the impression it is, while someone else might benefit being prescribed both for pain and breakthrough pain.) Tramadol and O-desmethyltramadol may be quantitated in blood, plasma or serum to monitor for abuse, confirm a diagnosis of poisoning or assist in the forensic investigation of a traffic or other criminal violation or a sudden death. Most commercial opiate immunoassay screening tests do not cross-react significantly with tramadol or its major metabolites, so chromatographic techniques must be used to detect and quantitate these substances. The concentrations of O-desmethyltramadol in the blood or plasma of a person who has taken tramadol are generally 10–20% those of the parent drug. Tramadol acts as a μ-opioid receptor agonist, serotonin releasing agent, norepinephrine reuptake inhibitor, NMDA receptor antagonist (IC50=16.5 μM), receptor2C5-HT antagonist (EC50=26nM), 5(α7) nicotinic acetylcholine receptor antagonist, TRPV1 receptor agonist, and 1M and 3M muscarinic acetylcholine receptor antagonist. The analgesic action of tramadol is not fully understood, but it is believed to work through modulation of serotonin and norepinephrine in addition to its relatively weak μ-opioid receptor agonism. The contribution of non-opioid activity is demonstrated by the fact that the analgesic effect of tramadol is not fully antagonised by the μ-opioid receptor antagonist naloxone. Tramadol is marketed as a racemic mixture of the (1R,2R)- and (1S,2S)-enantiomers with a weak affinity for the μ-opioid receptor (approximately 1/6000th that of morphine; Gutstein & Akil, 2006). The (1R,2R)-(+)-enantiomer is approximately four times more potent than the (1S,2S)-(–)-enantiomer in terms of μ-opioid receptor affinity and 5-HT reuptake, whereas the (1S,2S)-(–)-enantiomer is responsible for noradrenaline reuptake effects (Shipton, 2000). These actions appear to produce a synergistic analgesic effect, with (1R,2R)-(+)-tramadol exhibiting 10-fold higher analgesic activity than (1S,2S)-(–)-tramadol (Goeringer et al., 1997). The serotonergic-modulating properties of tramadol give it the potential to interact with other serotonergic agents. There is an increased risk of serotonin toxicity when tramadol is taken in combination with serotonin reuptake inhibitors (e.g., SSRIs), since these agents not only potentiate the effect of 5-HT but also inhibit tramadol metabolism.][ Tramadol is also thought to have some NMDA antagonistic effects, which has given it a potential application in neuropathic pain states. Tramadol has inhibitory actions on the 5-HT2C receptor. Antagonism of 5-HT2C could be partially responsible for tramadol's reducing effect on depressive and obsessive-compulsive symptoms in patients with pain and co-morbid neurological illnesses. 5-HT2C blockade may also account for its lowering of the seizure threshold, as 5-HT2C knockout mice display significantly increased vulnerability to epileptic seizures, sometimes resulting in spontaneous death. However, the reduction of seizure threshold could be attributed to tramadol's putative inhibition of GABA-A receptors at high doses. The overall analgesic profile of tramadol supports use in the treatment of intermediate pain, especially chronic pain. It is slightly less effective for acute pain than hydrocodone, but more effective than codeine. It has a dosage ceiling similar to codeine, a risk of seizures when overdosed, and a relatively long half-life making its potential for misuse relatively low amongst intermediate strength analgesics. Tramadol's primary active metabolite, O-desmethyltramadol, is a considerably more potent μ-opioid receptor agonist than tramadol itself. Thus, tramadol is in part a prodrug to O-desmethyltramadol. Similarly to tramadol, O-desmethyltramadol has also been shown to be a norepinephrine reuptake inhibitor, 5-HT2C receptor antagonist, and M1 and M3 muscarinic acetylcholine receptor antagonist.][ Structurally, tramadol closely resembles a stripped down version of codeine. Both codeine and tramadol share the 3-methyl ether group, and both compounds are metabolized along the same hepatic pathway and mechanism to the stronger opioid, phenol agonist analogs. For codeine, this is morphine, and for tramadol, it is the O-desmethyltramadol. When administered through IV, patients notice very little clinical difference in subjective potency compared to morphine. Structurally, tapentadol is the closest chemical relative of tramadol in clinical use. Tapentadol is also an opioid, but unlike both tramadol and venlafaxine, tapentadol represents only one stereoisomer and is the weaker of the two, in terms of opioid effect. Both tramadol and venlafaxine are racemic mixtures. Structurally, tapentadol also differs from tramadol in being a phenol, and not an ether. Also, both tramadol and venlafaxine incorporate a cyclohexyl moiety, attached directly to the aromatic, while tapentadol lacks this feature. In reality, the closest structural chemical entity to tapentadol in clinical use is the over-the-counter drug phenylephrine. Both share a meta phenol, attached to a straight chain hydrocarbon. In both cases, the hydrocarbon terminates in an amine. (1R,2R)-Tramadol   (1S,2S)-Tramadol
(1R,2R)-Tramadol     (1S,2S)-Tramadol
(1R,2S)-Tramadol   (1S,2R)-Tramadol
(1R,2S)-Tramadol     (1S,2R)-Tramadol The chemical synthesis of tramadol is described in the literature. Tramadol [2-(dimethylaminomethyl)-1-(3-methoxyphenyl)cyclohexanol] has two stereogenic centers at the cyclohexane ring. Thus, 2-(dimethylaminomethyl)-1-(3-methoxyphenyl)cyclohexanol may exist in four different configurational forms: The synthetic pathway leads to the racemate (1:1 mixture) of (1R,2R)-isomer and the (1S,2S)-isomer as the main products. Minor amounts of the racemic mixture of the (1R,2S)-isomer and the (1S,2R)-isomer are formed as well. The isolation of the (1R,2R)-isomer and the (1S,2S)-isomer from the diastereomeric minor racemate [(1R,2S)-isomer and (1S,2R)-isomer] is realized by the recrystallization of the hydrochlorides. The drug tramadol is a racemate of the hydrochlorides of the (1R,2R)-(+)- and the (1S,2S)-(–)-enantiomers. The resolution of the racemate [(1R,2R)-(+)-isomer / (1S,2S)-(–)-isomer] was described employing (R)-(–)- or (S)-(+)-mandelic acid. This process does not find industrial application, since tramadol is used as a racemate, despite known different physiological effects of the (1R,2R)- and (1S,2S)-isomers, because the racemate showed higher analgesic activity than either enantiomer in animals and in humans. Tramadol undergoes hepatic metabolism via the cytochrome P450 isozyme CYP2B6, CYP2D6 and CYP3A4, being O- and N-demethylated to five different metabolites. Of these, -desmethyltramadolO is the most significant since it has 200 times the μ-affinity of (+)-tramadol, and furthermore has an elimination half-life of nine hours, compared with six hours for tramadol itself. As with codeine, in the 6% of the population that have increased CYP2D6 activity (increased metabolism), there is therefore an increased analgesic effect. Those with decreased CYP2D6 activity will experience less analgesia. Phase II hepatic metabolism renders the metabolites water-soluble, which are excreted by the kidneys. Thus, reduced doses may be used in renal and hepatic impairment. O-Desmethyltramadol, as well as tramadol's inactive metabolite, N-desmethyltramadol, both metabolize into the pharmacologically active N,O-didesmethyltramadol via CYP2D6. Tramadol (as the racemic, cis-hydrochloride salt), is available as a generic in the U.S. from any number of different manufacturers, including Amneal, Caraco, Mylan, Cor Pharma, Mallinckrodt, Pur-Pak, APO, Teva, and many more. Typically, the generic tablets are sold in 50 mg tablets. Brand name formulations include Ultram ER, and the original Ultram from Ortho-McNeil, (cross-licensed from Grünenthal GmbH) which is now produced by Janssen. The extended-release formulation of tramadol—which, among other factors, was intended to be more abuse-deterrent than the instant release—allegedly possesses more abuse liability than the instant release formulation.][ The U.S. Food and Drug Administration (FDA) approved tramadol in March 1995 and an extended-release (ER) formulation in September 2005. It is covered by U.S. patents nos. 6,254,887 and 7,074,430. The FDA lists the patents as scheduled for expiration on May 10, 2014. However, in August 2009, U.S. District Court for the District of Delaware ruled the patents invalid, which, if it survives appeal, would permit manufacture and distribution of generic equivalents of Ultram ER in the United States. Tramadol is not a federally controlled substance in the United States; however, Arkansas, Kentucky, Illinois, Mississippi, New York, North Dakota, Ohio, Oklahoma, Tennessee, West Virginia, Wyoming and the U.S. military have classified Tramadol as a schedule IV controlled substance under state law. Other states have legislation pending concerning scheduling tramadol. Sweden, as of May 2008, has chosen to classify tramadol as a controlled substance in the same way as codeine and dextropropoxyphene. This means that the substance is a scheduled drug. But unlike codeine and dextropropoxyphene, a normal prescription can be used at this time. In Mexico, combined with paracetamol and sold under the brand name Tramacet, it is widely available without a prescription, but this is currently under re-evaluation. In most Asian countries such as the Philippines, it is sold as a capsule under the brand name Tramal, where it is mostly used to treat labor pains. Grünenthal GmbH, which still owns the patent on tramadol, has cross-licensed the drug to pharmaceutical companies internationally. Thus, tramadol is marketed under many trade names around the world, including: Tramadol may be used to treat post-operative, injury-related, and chronic (e.g., cancer-related) pain in dogs and cats as well as rabbits, coatis, many small mammals including rats and flying squirrels, guinea pigs, ferrets, and raccoons. Tramadol comes in ampules in addition to the tablets, capsules, powder for reconstitution, and oral syrups and liquids; the fact that its characteristic taste is distasteful to dogs, but can be masked in food, makes for a means of administration. No data that would lead to a definitive determination of the efficacy and safety of tramadol in reptiles or amphibians are available, and, following the pattern of all other drugs, it appears that tramadol can be used to relieve pain in marsupials, such as North American opossums, short-tailed opossums, sugar gliders, wallabies, and kangaroos among others. Tramadol for animals is one of the most reliable and useful active principles available to veterinarians for treating animals in pain. It has a dual mode of action: weak mu agonism and mono-amine reuptake inhibition, which produces mild anti-anxiety results. This is an advantage because the use of some non-steroidal anti-inflammatory substances in these animals may be dangerous.][ When animals are administered tramadol, adverse reactions can occur. The most common are constipation, upset stomach, decreased heart rate.][ In case of overdose, mental alteration, pinpoint pupils and seizures may appear. In such cases, veterinarians should evaluate the correct treatment for these events. Some contraindications have been noted in treated animals taking certain other drugs. Tramadol should not be co-administered with selegiline or any other psychoactive class of medication such as selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants, or monoamine oxidase inhibitors.][ In animals, tramadol is removed from the body via liver and kidney excretion. Animals suffering from diseases in these systems should be monitored by a veterinarian, as it may be necessary to adjust the dose.

M: CNS anat (n/s/m/p/4/e/b/d/c/a/f/l/g)/phys/devp noco (m/d/e/h/v/s)/cong/tumr, sysi/epon, injr proc, drug (N1A/2AB/C/3/4/7A/B/C/D)
Serotonin syndrome is a potentially life-threatening drug reaction that may occur following therapeutic drug use, inadvertent interactions between drugs, overdose of particular drugs, or the recreational use of certain drugs. Serotonin syndrome is not an idiopathic drug reaction; it is a predictable consequence of excess serotonergic activity at central nervous system (CNS) and peripheral serotonin receptors. For this reason, some experts strongly prefer the terms serotonin toxicity or serotonin toxidrome because these more accurately reflect the fact that it is a form of poisoning. It may also be called serotonin sickness, serotonin storm, serotonin poisoning, hyperserotonemia, or serotonergic syndrome. The excess serotonin activity produces a spectrum of specific symptoms including cognitive, autonomic, and somatic effects. The symptoms may range from barely perceptible to fatal. Numerous drugs and drug combinations have been reported to produce serotonin syndrome. Diagnosis of serotonin syndrome includes observing the symptoms produced and a thorough investigation of the patient's history. The syndrome has a characteristic picture but can be mistaken for other illnesses in some people, particularly those with neuroleptic malignant syndrome. No laboratory tests can currently confirm the diagnosis. Treatment consists of discontinuing medications which may contribute and in moderate to severe cases administering a serotonin antagonist. An important adjunct treatment includes controlling agitation with benzodiazepine sedation. The high-profile case of Libby Zion, who is generally accepted to have died from serotonin syndrome, resulted in changes to graduate medical education in New York State. Symptom onset is usually rapid, often occurring within minutes. Serotonin syndrome encompasses a wide range of clinical findings. Mild symptoms may only consist of increased heart rate, shivering, sweating, dilated pupils, myoclonus (intermittent tremor or twitching), as well as overresponsive reflexes. Moderate intoxication includes additional abnormalities such as hyperactive bowel sounds, high blood pressure and hyperthermia; a temperature as high as is common in moderate intoxication. The overactive reflexes and clonus in moderate cases may be greater in the lower limbs than in the upper limbs. Mental status changes include hypervigilance and agitation. Severe symptoms include severe increases in heart rate and blood pressure that may lead to shock. Temperature may rise to above in life-threatening cases. Other abnormalities include metabolic acidosis, rhabdomyolysis, seizures, renal failure, and disseminated intravascular coagulation; these effects usually arising as a consequence of hyperthermia. The symptoms are often described as a clinical triad of abnormalities: A large number of medications either alone in high dose or in combination can produce serotonin syndrome. Many cases of serotonin toxicity occur in patients who have ingested drug combinations that synergistically increase synaptic serotonin. It may also occur in patients following an overdose of a single serotonergic agent. The combination of MAOIs and other serotonin agonists or precursors pose a particularly severe risk of a life-threatening serotonin syndrome. Many MAOIs inhibit monoamine oxidase irreversibly, so that the enzyme cannot function until it has been replaced by the body, which can take at least four weeks. Many medications may have been incorrectly thought to cause serotonin syndrome. For example, some case reports have implicated atypical antipsychotics in serotonin syndrome, but it appears based on their pharmacology that they are unlikely to cause the syndrome. It has also been suggested that mirtazapine has no significant serotonergic effects, and is therefore not a dual action drug. Bupropion has also been suggested to cause serotonin syndrome, although as there is no evidence that it has any significant serotonergic activity, it is thought unlikely to produce the syndrome. In 2006 the United States Food and Drug Administration issued an alert suggesting that the combined use of SSRIs or SNRIs and triptan medications or sibutramine could potentially lead to severe cases of serotonin syndrome. This has been disputed by other researchers as none of the cases reported by the FDA met the Hunter criteria for serotonin syndrome. The condition has however occurred in surprising clinical situations, and because of phenotypic variations among individuals, it has been associated with unexpected drugs, including mirtazapine. The relative risk and severity of serotonergic side effects and serotonin toxicity, with individual drugs and combinations, is complex. Serotonin syndrome has been reported in patients of all ages, including the elderly, children, and even newborn infants due to in utero exposure. The serotonergic toxicity of SSRIs increases with dose, but even in over-dose it is insufficient to cause fatalities from serotonin syndrome in healthy adults. Elevations of central nervous system serotonin will typically only reach potentially fatal levels when drugs with different mechanisms of action are mixed together. Various drugs, other than SSRIs, also have clinically significant potency as serotonin reuptake inhibitors, (e.g. tramadol, amphetamine, and MDMA) and are associated with severe cases of the syndrome. Serotonin is a neurotransmitter involved in multiple states including aggression, pain, sleep, appetite, anxiety, depression, migraine, and vomiting.][ In humans the effects of excess serotonin were first noted in 1960 in patients receiving a monoamine oxidase inhibitor (MAOI) and tryptophan. The syndrome is caused by increased serotonin in the central nervous system. It was originally suspected that agonism of receptors1A5-HT in central grey nuclei and the medulla was responsible for the development of the syndrome. Further study has determined that overstimulation of primarily the receptors2A5-HT appears to contribute substantially to the condition. The 5-HT1A receptor may still contribute through a pharmacodynamic interaction in which increased synaptic concentrations of a serotonin agonist saturate all receptor subtypes. Additionally, noradrenergic CNS hyperactivity may play a role as CNS norepinephrine concentrations are increased in serotonin syndrome and levels appear to correlate with the clinical outcome. Other neurotransmitters may also play a role; NMDA receptor antagonists and GABA have been suggested as affecting the development of the syndrome. Serotonin toxicity is more pronounced following supra-therapeutic doses and overdoses, and they merge in a continuum with the toxic effects of overdose. A postulated 'spectrum concept' of serotonin toxicity emphasises the role that progressively increasing serotonin levels play in mediating the clinical picture as side effects merge into toxicity. The dose-effect relationship is the effects of progressive elevation of serotonin, either by raising the dose of one drug, or combining it with another serotonergic drug which may produce large elevations in serotonin levels. There is no laboratory test for serotonin syndrome. Therefore diagnosis is by symptom observation and investigation of the patient's history. Several diagnostic criteria have been proposed. The first rigorously evaluated criteria were introduced in 1991 by Harvey Sternbach, a professor of psychiatry at UCLA. Researchers in Australia later developed the Hunter Toxicity Criteria Decision Rules, which have better sensitivity and specificity, 84% and 97%, respectively, when compared with the gold standard of diagnosis by a medical toxicologist. As of 2007, Sternbach's criteria were still the most commonly used. The most important symptoms for diagnosing serotonin syndrome are tremor, akathisia, or clonus (spontaneous, inducible and ocular). Physical examination of the patient should include assessment of deep-tendon reflexes and muscle rigidity, the dryness of the oral mucosa, the size and reactivity of the pupils, the intensity of bowel sounds, skin color, and the presence or absence of sweating. The patient's history also plays an important role in diagnosis, investigations should include inquries about the use of prescription and over-the-counter drugs, illicit substances, and dietary supplements, as all these agents have been implicated in the development of serotonin syndrome. To fulfill the Hunter Criteria, a patient must have taken a serotonergic agent and meet one of the following conditions: Serotonin toxicity has a characteristic picture which is generally hard to confuse with other medical conditions, but in some situations it may go unrecognized because it may be mistaken for a viral illness, anxiety, neurological disorder, anticholinergic poisoning, sympathomimetic toxicity, or worsening psychiatric condition. The condition most often confused with serotonin syndrome is neuroleptic malignant syndrome (NMS). The clinical features of neuroleptic malignant syndrome and serotonin syndrome share some features which can make differentiating them difficult. In both conditions, autonomic dysfunction and altered mental status develop. However, they are actually very different conditions with different underlying dysfunction (serotonin excess vs dopamine blockade). Both the time course and the clinical features of NMS differ significantly from those of serotonin toxicity. Serotonin toxicity has a rapid onset after the administration of a serotonergic drug and responds to serotonin blockade such as drugs like chlorpromazine and cyproheptadine. Dopamine receptor blockade (NMS) has a slow onset and typically evolves over several days after administration of a neuroleptic drug and responds to dopamine agonists such as bromocriptine. Differential diagnosis may become difficult in patients recently exposed to both serotonergic drugs and neuroleptic drugs. Features that are classically present in NMS, that are useful for differentiating the two, are bradykinesia and extrapyramidal "lead pipe" rigidity, whereas serotonin syndrome causes hyperkinesia and clonus. Management is based primarily on stopping the usage of the precipitating drugs, the administration of serotonin antagonists such as cyproheptadine, and supportive care including the control of agitation, the control of autonomic instability, and the control of hyperthermia. Additionally, those who ingest large doses of serotonergic agents may benefit from gastrointestinal decontamination with activated charcoal if it can be administered within an hour of overdose. The intensity of therapy depends on the severity of symptoms. If the symptoms are mild, treatment may only consist of discontinuation of the offending medication or medications, offering supportive measures, giving benzodiazepines for myoclonus, and waiting for the symptoms to resolve. Moderate cases should have all thermal and cardiorespiratory abnormalities corrected and can benefit from serotonin antagonists. The serotonin antagonist cyproheptadine is the recommended initial therapy, although there have been no controlled trials demonstrating its efficacy for serotonin syndrome. Despite the absence of controlled trials, there are a number of case reports detailing apparent improvement after patients have been administered cyproheptadine. Animal experiments also suggest a benefit from serotonin antagonists. Cyproheptadine is only available as tablets and therefore can only be administered orally or via a nasogastric tube; it is unlikely to be effective in patients administered activated charcoal and has limited use in severe cases. Additional pharmacological treatment for severe case includes administering atypical antipsychotic drugs with serotonin antagonist activity such as olanzapine. Critically ill patients should receive the above therapies as well as sedation or neuromuscular paralysis. Patient who have autonomic instability such as low blood pressure require treatment with direct-acting sympathomimetics such as epinephrine, norepinephrine, or phenylephrine. Conversely, hypertension or tachycardia can be treated with short-acting antihypertensive drugs such as nitroprusside or esmolol; longer acting drugs such as propranolol should be avoided as they may lead to hypotension and shock. Specific treatment for some symptoms may be required. One of the most important treatments is the control of agitation with benzodiazepines. Physical restraints are not recommended for agitation or delirium as they may contribute to mortality by enforcing isometric muscle contractions that are associated with severe lactic acidosis and hyperthermia. If physical restraints are necessary for severe agitation they must be rapidly replaced with pharmacological sedation. The agitation can cause a large amount of muscle breakdown. This breakdown can cause severe damage to the kidneys through a condition called rhabdomyolysis. Treatment for hyperthermia includes reducing muscle over-activity via sedation with a benzodiazepine. More severe cases may require muscular paralysis with vecuronium, intubation, and artificial ventilation. Succinylcholine is not recommended for muscular paralysis as it may increase the risk of cardiac dysrhythmia from hyperkalemia associated with rhabdomyolysis. Antipyretic agents are not recommended as the increase in body temperature is due to muscular activity not a hypothalamic temperature set point abnormality. Upon the discontinuation of serotonergic drugs, most cases of serotonin syndrome resolve within 24 hours, although in some cases delirium may persist for a number of days. Symptoms typically persist for a longer time frame in patients taking drugs which have a long elimination half-life, active metabolites, or a protracted duration of action. Cases have reported muscle pain and weakness persisting for months, and antidepressant discontinuation may contribute to ongoing features. Following appropriate medical management, serotonin syndrome is generally associated with a favorable prognosis. Epidemiological studies of serotonin syndrome are difficult as many physicians are unaware of the diagnosis or they may miss the syndrome due to its variable manifestations. In 1998 a survey conducted in England found that 85% of the general practitioners that had prescribed the antidepressant nefazodone were unaware of serotonin syndrome. The incidence may be increasing as a larger number of pro-serotonergic drugs (drugs which increase serotonin levels) are now being used in clinical practice. One post-marketing surveillance study identified an incidence of 0.4 cases per 1000 patient-months for patients who were taking nefazodone. Additionally, around 14 to 16 percent of persons who overdose on SSRIs are thought to develop serotonin syndrome. The most widely recognized example of serotonin syndrome was the death of Libby Zion in 1984. Libby was a freshman at Bennington College at her death on March 5, 1984, at age 18. She died within 8 hours of her emergency admission to the New York Hospital Cornell Medical Center. She had an ongoing history of depression, and came to the Manhattan hospital on the evening of March 4, 1984, with a fever, agitation and "strange jerking motions" of her body. She also seemed disoriented at times. The emergency room physicians were unable to diagnose her condition definitively, but admitted her for hydration and observation. Her death was caused by a combination of pethidine (aka meperidine (Demerol)) and phenelzine. The doctor who prescribed the pethidine was a medical intern. The case had an impact on graduate medical education and residency work hours. Limits were set on working hours for medical post graduates, commonly referred to as interns or residents, in hospital training programs, and they also now require closer senior physician supervision. M: CNS anat (n/s/m/p/4/e/b/d/c/a/f/l/g)/phys/devp noco (m/d/e/h/v/s)/cong/tumr, sysi/epon, injr proc, drug (N1A/2AB/C/3/4/7A/B/C/D) M: TOX gen / txn pto ant
InChI=1S/C22H29NO2/c1-5-21(24)25-22(18(2)17-23(3)4,20-14-10-7-11-15-20)16-19-12-8-6-9-13-19/h6-15,18H,5,16-17H2,1-4H3/t18-,22+/m1/s1Yes 
Key:XLMALTXPSGQGBX-GCJKJVERSA-NYes  Dextropropoxyphene is an analgesic in the opioid category, patented (1955) and manufactured by Eli Lilly and Company. It is intended to treat mild pain and also has antitussive and local anaesthetic effects. The drug has been taken off the market in Europe and the US due to concerns of fatal overdoses and heart arrhythmias. An estimated 10 million patients have used these products. Dextropropoxyphene is sometimes combined with paracetamol or acetylsalicylic acid. Trade names include Darvocet-N and Di-Gesic Darvon with APAP for dextropropoxyphene and paracetamol and Darvon with ASA for dextropropoxyphene and aspirin. The British Approved Name (i.e. the generic name of the active ingredient) of the paracetamol/dextropropoxyphene preparation is co-proxamol (sold under a variety of brand names); however, it has been withdrawn since 2007, and is no longer available to new patients. The paracetamol combination(s) are known as Capadex or Di-Gesic in Australia, Lentogesic in South Africa, and Di-Antalvic in France (unlike co-proxamol, which is an approved name, these are all brand names). Synonymy: Dextropropoxyphen is known under several names so: IUPAC rules establish that it is to be called desoxypropiophen. Dextropropoxyphene, like codeine, is a weak opioid, known to cause dependency among recreational users. Codeine is more commonly used; however, as codeine is, in essence, a prodrug that requires in vivo metabolism for efficacy, it is ineffective for some individuals with the "poor metabolizer" genotype of the liver cytochrome P450 enzyme CYP2D6. In people with this low-function isoform, dextropropoxyphene is particularly useful, as its metabolism does not require CYP2D6. It is also used for patients with digestive complaints, as it is less liable to worsen their symptoms. Dextropropoxyphene has been found to be helpful in relieving the symptoms of restless legs syndrome. In pure form, dextropropoxyphene is commonly used to ease the withdrawal symptoms in people addicted to opioids. Being very weak in comparison to commonly abused opioids, dextropropoxyphene can only act as a "partial" substitute. It does not have much effect on mental cravings; however, it can be effective in alleviating physical withdrawal effects, such as muscle cramps. Dextropropoxyphene is contraindicated in patients allergic to paracetamol (acetaminophen) or dextropropoxyphene, in alcoholics, and in combination with amphetamine, where CNS stimulation is potentiated and fatal convulsions can occur in dextropropoxyphene overdosage. Dextropropoxyphene is not intended for use in patients who are prone to suicide, anxiety, panic, or addiction. Dextropropoxyphene acts as a mu-opioid receptor agonist. It also acts as a potent, noncompetitive 4β3α neuronal nicotinic acetylcholine receptor antagonist, as well as a weak serotonin reuptake inhibitor. Overdose is commonly broken into two categories: liver toxicity (from paracetamol poisoning) and dextropropoxyphene overdose. Many users experience toxic effects from the paracetamol (acetaminophen) in pursuit of the endlessly increasing dose required for pain relief. They suffer acute liver toxicity, which causes severe stomach pains, nausea, and vomiting (all of which are increased by light or stimulation of the sense of sight). An overdose of dextropropoxyphene may lead to various systemic effects. Excessive opioid receptor stimulation is responsible for the CNS depression, respiratory depression, aspiration pneumonia, miosis, and gastrointestinal effects seen in propoxyphene poisoning. It may also account for mood- or thought-altering effects. In addition, both propoxyphene and its metabolite norpropoxyphene have local anesthetic effects at concentrations about 10 times those necessary for opioid effects. Norpropoxyphene is a more potent local anesthetic than propoxyphene, and they are both more potent than lidocaine. Local anesthetic activity appears to be responsible for the arrhythmias and cardiovascular depression seen in propoxyphene poisoning. Both propoxyphene and norpropoxyphene are potent blockers of cardiac membrane sodium channels and are more potent than lidocaine, quinidine, and procainamide in this respect. As a result, propoxyphene and norpropoxyphene appear to have the characteristics of a Vaughn-Williams Class Ic antiarrhythmic. These direct cardiac effects include decreased heart rate (i.e. cardiovascular depression), decreased contractility, and decreased electrical conductivity (i.e., increased PR, AH, HV, and QRS intervals). These effects appear to be due to their local anesthetic activity and are not reversed by naloxone. Widening of the QRS complex appears to be a result of a quinidine-like effect of propoxyphene, and sodium bicarbonate therapy appears to have a positive direct effect on the QRS dysrhythmia. Seizures may result from either opioid or local anesthetic effects. Pulmonary edema may result from direct pulmonary toxicity, neurogenic/anoxic effects, or cardiovascular depression. Balance disorder is possible, with risk of falls from standing height. Propoxyphene was initially introduced as propoxyphene hydrochloride. Shortly before the patent on propoxyphene expired, propoxyphene napsylate form was introduced to the market. Napsylate salt (the salt of naphthalenesulfonic acid) is claimed to be less prone to abuse, because it is almost insoluble in water, so cannot be used for injection. Napsylate also gives lower peak blood level. Because of different molecular mass, a dose of 100 mg of propoxyphene napsylate is required to supply an amount of propoxyphene equivalent to that present in 65 mg of propoxyphene hydrochloride. Before the FDA-directed recall, dextropropoxyphene HCl was available in the United States as a prescription formulation with paracetamol (acetaminophen) in ratio from 30 mg / 600 mg to 100 mg / 650 mg (or 100 mg / 325 mg in the case of Balacet), respectively. These are usually named Darvocet. Darvon is a pure propoxyphene preparation that does not contain paracetamol. In Australia, dextropropoxyphene is available on prescription, both as a combined product (32.5 mg dextropropoxyphene per 325 mg paracetamol branded as Di-gesic, Capadex, or Paradex; it is also available in pure form (100 mg capsules) known as Doloxene. Detectable levels of propoxyphene/dextropropoxyphene may stay in a person's system for up to 9 days after last dose and can be tested for specifically in nonstandard urinalysis, but may remain in the body longer in tiny amounts. Propoxyphene will not show up on standard opiate/opioid tests because it is not chemically related to opiates as part of the OPI or OPI 2000 panels, which detect morphine and related compounds. It is most closely related to methadone. Dextropropoxyphene is subject to some controversy: while many physicians prescribe it for a wide range of mildly to moderately painful symptoms, as well as for treatment of diarrhea, many others refuse to prescribe it, citing limited effectiveness.][ In addition, the therapeutic index of dextroproxyphene is relatively small. Caution should be used when administering dextropropoxyphene, particularly with children and the elderly and with patients who may be pregnant or breast feeding;][ other reported problems include kidney, liver or respiratory disorders, and prolonged use. Attention should be paid to concomitant use with tranquilizers, antidepressants or excess alcohol. Darvon, a dextropropxyphene formulation made by Eli Lilly, which had been on the market for 25 years, came under heavy fire in 1978 by consumer groups that said it was associated with suicide.][ Darvon was never withdrawn from the market, but Lilly has waged a sweeping, and largely successful, campaign][ among doctors, pharmacists and Darvon users to defend the drug as safe when it is used in proper doses and not mixed with alcohol. On November 19, 2010, the FDA banned all sale of Darvon and Darvocet. In Australia, both pure dextropropoxyphene capsules (as napsylate, 100 mg), marketed as Doloxene, and combination tablets and capsules (with paracetamol) all containing 32.5 mg dextropropoxyphene HCl with 325 mg paracetamol, which are currently available on prescription were supposed to be withdrawn from 1 March 2012, but Aspen Pharma sought a review in the Administrative Appeals Tribunal which resulted in a stay in the ban until a hearing scheduled for late May. In November 2007, the European Commission requested the European Medicines Agency (EMA) to review the safety and effectiveness of dextropropoxyphene based medicines and on 25 June 2009 the EMA recommended a gradual withdrawal throughout the European Union. The EMA's conclusion was based on evidence that dextropropoxyphene-containing medicines were weak painkillers, the combination of dextropropoxyphene and paracetamol was no more effective than paracetamol on its own, and the difference between the dose needed for treatment and a harmful dose (the "therapeutic index") was too small. In February 2010, Medsafe announced Paradex and Capadex (forms of dextropropoxyphene) were being withdrawn from the marketplace due to health issues, and withdrawal in other countries. In Sweden, physicians had long been discouraged by the medical products agency to prescribe dextropropoxyphene due to the risk of respiratory depression and even death when taken with alcohol. Physicians have earlier been recommended to prescribe products with only dextropropoxyphene and not to patients with a history of drug abuse, depression or suicidal tendencies. Products with mixed active ingredients were taken off the market and only products with dextropropoxyphene were allowed to be sold. Dextropoxyphene was de facto narcotica labelled. As of March 2011, all products containing the substance are withdrawn because of safety issues after a European Commission decision. It was discussed at the time that people who abuse alcohol and other substances and take combination dextropoxyphene / acetaminophen (paracetamol) may need to take many combination tablets to reach euphoria, because the amount of dextropropoxyphene per tablet is relatively low (30–40 mg). The ingested paracetamol - the other component - may then reach liver toxic levels. In the case of alcoholics, who often already have damaged livers, even a relatively small overdose with paracetamol may produce hepatotoxicity, liver necrosis and liver failure. This toxicity with the combination of overdosed dextroproxyphene (with its CNS/respiratory depression/vomit with risk for aspiration pneumonia, as well as cardiotoxicity) and paracetamol-induced liver damage can result in disaster or death. In the United Kingdom, preparations containing only dextropropoxyphene were discontinued in 2004. In 2007, the Medicines and Healthcare Products Regulatory Agency removed the licence for co-proxamol. From then on in the UK, co-proxamol is only available on a named patient basis, for long-term chronic pain and only to those who have already been prescribed this medicine. Its withdrawal from the UK market is a result of concerns relating to its toxicity in overdose (even small overdoses can be fatal), and dangerous reaction with alcohol. Recreational use in the UK is uncommon. Many patients have been prescribed alternative combinations of drugs as a replacement. The motivation for the withdrawal of co-proxamol was the reduction in suicides and a key part of the agency's justification of its decision was based upon studies showing co-proxamol was no more effective than paracetamol alone in pain management. Prescribing authorities, such as the Royal College of General Practitioners, unanimously recommended withdrawal, while patients who responded to the agency's request for information tended to want to continue treatment. Many doctors, as well as patients, believe clinical experience shows co-proxamol is more effective than paracetamol alone.][ The co-proxamol preparations available in the UK contained a subtherapeutic dose of paracetamol, 325 mg per tablet. Patients were warned not to take more than eight tablets in one day, a total dose of 2600 mg paracetamol per day. This is in comparison to the 4000-mg daily limit on paracetamol alone, a significantly higher dose. Despite this reduced level, patients were still at a high risk of overdose; coproxamol was second only to tricyclic antidepressants as the most common prescription drugs used in overdose. Following the reduction in prescribing in 2005–2007, prior to its complete withdrawal, the number of deaths associated with the drug dropped significantly. Additionally, patients have not substituted other drugs as a method of overdose. The decision to withdraw coproxamol has met with some controversy; it has been brought up in the House of Commons on two occasions, 13 July 2005 and on 17 January 2007. Patients have found alternatives to co-proxamol either too strong, too weak, or with intolerable side effects.][ During the House of Commons debates, it is quoted that originally some 1,700,000 patients in the UK were prescribed co-proxamol. Following the phased withdrawal, this has eventually been reduced to 70,000. However, it appears this is the residual pool of patients who cannot find alternate analgesia to co-proxamol.][ The safety net of prescribing co-proxamol after licence withdrawal from 31 December 2007, on a "named patient" basis where doctors agree there is a clinical need, has been rejected by most UK doctors][ because the wording that "responsibility will fall on the prescriber" is unacceptable to most doctors. Some patients intend to take the case to the European Court of Human Rights. However, the European Medicines Agency has recently backed the agency's decision, and recommended in June 2009 that propoxyphene preparations be withdrawn across the European Union. In January 2009, an FDA advisory committee voted 14 to 12 against the continued marketing of propoxyphene products, based on its weak pain-killing abilities, addictiveness, association with drug deaths and possible heart problems, including arrhythmia. A subsequent re-evaluation resulted in a July 2009 recommendation to strengthen the boxed warning for propoxyphene to reflect the risk of overdose. Dextropropoxyphene subsequently carried a black box warning in the U.S., stating: Propoxyphene should be used with extreme caution, if at all, in patients who have a history of substance/drug/alcohol abuse, depression with suicidal tendency, or who already take medications that cause drowsiness (e.g., antidepressants, muscle relaxants, pain relievers, sedatives, tranquilizers). Fatalities have occurred in such patients when propoxyphene was misused. Because of potential for side effects, this drug is on the list for High Risk Medications in the elderly. On November 19, 2010, the FDA requested the cessation of all sale of Darvon and Darvocet from the US drug market due to heart arrhythmia in patients who took the drug. The drug Darvocet may also be involved in combined drug intoxication, because it may lead to confusion in patients and physicians. Many doctors are commonly switching to tramadol, because it is generally considered safer.][ However, in the same way codeine is a prodrug that requires in vivo metabolism for efficacy, tramadol is as well. So in the same manner as codeine, tramadol can be ineffective for individuals with liver enzyme CYP2D6 deficiencies. This can sometimes make propoxyphene a "last resort" for minor pain relief in people with this condition, as even much stronger opioids such as hydrocodone and oxycodone will also be slightly less effective as much as 10% of these medications will be converted to the much stronger hydromorphone and oxymorphone, respectively, in typical patients. In these cases medications like morphine or tapentadol can be used as they do not require further metabolism to be effective. However, these medications are many times stronger than propoxyphene, and come with their own set of risks, including a much larger risk of overdose and addiction than propoxyphene. On December 1, 2010, Health Canada and Paladin Labs Inc. announced the voluntary recall and withdrawal of Darvon-N from the Canadian market and the discontinuation of sale of Darvon-N. On June 12, 2013, the Indian government suspended the manufacture, sale, and distribution of the drug under Section 26A of the 1940 Drugs and Cosmetic Act. High toxicity and relatively easy availability made propoxyphene a drug of choice for right to die societies. It is listed in Dr. Philip Nitschke's The Peaceful Pill Handbook and Dr. Pieter Admiraal's Guide to a Humane Self-Chosen Death. "With the withdrawal of the barbiturate sleeping tablets from the medical prescribing list, propoxyphene has become the most common doctor-prescribed medication used by seriously ill people to end their lives." The slang name for the combination of propoxyphene and other drugs used for suicide is "Darvon cocktail". M: CNS anat (n/s/m/p/4/e/b/d/c/a/f/l/g)/phys/devp noco (m/d/e/h/v/s)/cong/tumr, sysi/epon, injr proc, drug (N1A/2AB/C/3/4/7A/B/C/D)
Frankie Boyle’s Tramadol Nights is a comedy sketch show created by Frankie Boyle, starring Boyle himself alongside Jim Muir, Tom Stade, Robert Florence and Thaila Zucchi. In October 2009, Boyle announced online that he would be leaving BBC panel show Mock the Week after seven series to focus on his tour and "some other funny things I'm writing". Later that month, he told The Daily Mirror that his new material would include a comedy sketch show for Channel 4, without censoring any of the black humour he had become known for. An appearance on Friday Night with Jonathan Ross followed, when Boyle revealed that the show was originally called Deal with This, Retards, but had to be changed to avoid offence. The show was consequently renamed Frankie Boyle's Tramadol Nights (a reference to the opioid drug Tramadol and the J. G. Ballard novel Cocaine Nights), with a broadcast date of November–December 2010. The show mixes pre-recorded comedy sketches with stand-up routines before a studio audience who are "gleefully abused" by Boyle. The show received a mixed critical reception. The first episode, broadcast on 30 November 2010 after an advertising campaign on London buses, attracted a "modest" audience (1.54 million viewers including the time-shifted repeat the same evening). The free daily newspaper Metro applauded the first episode's blend of stand-up and sketches, that "cantered gleefully – but never gratuitously - past the boundaries of taste and decency" with "some fantastically acerbic rants about religious people and the mentally ill." The Independent's Rhiannon Harries felt "the best of the sketches were those that satirised the bland inanity of TV culture" but was "less comfortable with the jokes about mental illness" that more or less "conflated religion and autism", concluding that there was "something very brittle about the laughter. The world seems a meaner place after listening to Boyle." The Liverpool Echo observed that "in a former life, not so long ago, Boyle was the best thing about Mock the Week" but thought the new series' uncompromising material "was, somehow, over the top and below the belt at the same time," culminating in a parody of Knight Rider that was "one of the most tedious and unfunny sketches in the history of tedious and unfunny sketches." In The Guardian, John Crace, noting that the absence of previews was usually PR speak for "We don't think it's much good and we want to avoid it getting a kicking," implied that Boyle's standup sequences were re-hashed from his recent "least exciting" tour. The conclusion that Boyle – known for "heartless sensitivity-baiting and not much else" – has been given "enough rope to hang himself" is difficult to resist. But "there are flashes of the caustic wit that make him great" and "even to those who've heard his jokes before, there are laugh-out-loud moments." Writing in The Scotsman, Aidan Smith said he didn't find any of the jokes very funny and the filmed sketches "showed up Boyle's limitations as a comic actor." MSN's Stuart Bak wondered whether Frankie Boyle was still funny. In sketch form, his material is "neither particularly offensive nor particularly funny, but a bit run-of-the-mill and even, at times, embarrassingly awful" so Boyle should "stick to the stand-up." The British Comedy Guide branded the show "disappointing", citing "over-long sketches" and an "almost childish fixation on sex". On December 7 the second episode (including the time-shifted repeat) reached 1.14 million viewers, down 26% on week one. Metro withdrew its support, claiming "laughs were thin on the ground" in the second week and that in the third episode "almost without exception, the sketches were wholly unfunny and the in-house audience seemed to be struggling to raise even the smallest of titters." The final episode was broadcast on December 29 and averaged an audience of 575,000. In December 2010, both Katie Price and Peter Andre were said to have been left "absolutely disgusted and sickened" by a joke in the 7 December 2010 broadcast about Price's disabled son, Harvey (then 8 years old). On the show, Boyle said: "Apparently Jordan [Katie Price] and Peter Andre are fightin' each other over custody of Harvey - well eventually one of them'll lose and have to keep him. I have a theory that Jordan married a cage fighter cause she needed someone strong enough to stop Harvey from fuckin' her." In a response, Katie Price said: "Harvey Price is a little miracle. Every day he overcomes so many difficulties with the help of family and medical experts and has so many tiny battles to win due to his medical problems and autism. I love him and am deeply proud to be his mother. If Mr Boyle had a tenth of his courage and decency he would know that to suggest, let alone think funny, that Harvey may sexually attack me is vile and deeply unfair. Mr Boyle clearly has serious issues and those that give him a TV platform to say such disgusting things need to look at themselves very honestly." Peter Andre's representative also responded to the comments made by Boyle and said "We're all disgusted by these comments. Peter is angry and very upset at Harvey being mocked in this way. Children, especially a disabled youngster, should be off-limits." Both have confirmed that they are seeking legal action and have written a complaint to Channel 4 regarding Boyle's jokes with Katie saying "To bully this unbelievably brave child is despicable; to broadcast it is to show a complete and utter lack of judgement. I have asked my lawyers to write to Channel 4." The charity Mencap described Boyle's joke as a "disgusting" attack on a disabled child. In April 2011 Ofcom upheld 500 complaints about the incident and censured Boyle and Channel 4 for broadcasting the jokes, which had been personally cleared by Channel 4's Chief Executive David Abraham, ruling that the material appeared to directly target and mock the mental and physical disabilities of a known eight year-old child who had not himself chosen to be in the public eye. "As such, Ofcom found that the comments had considerable potential to be highly offensive to the audience." In a later episode, Frankie was criticised by some media outlets for using racially offensive terms. Boyle used the term 'Pakis' during a joke criticising prioritisation of British and western war casualties over others in UK news media. In July 2011, the Daily Mirror published an article which strongly criticised Boyle, describing him as a 'racist comedian'. In response, he sued the Mirror for libel, and was awarded more than £54,000 damages after a High Court jury found he had been libelled. He donated the money to charity. The series was released on DVD on 21 November 2011. The Harvey Price joke from episode two has been cut from the DVD version.
InChI=1S/C8H9NO2/c1-6(10)9-7-2-4-8(11)5-3-7/h2-5,11H,1H3,(H,9,10)Yes 
Key:RZVAJINKPMORJF-UHFFFAOYSA-NYes  Paracetamol INN ( or ), or acetaminophen USAN , chemically named N-acetyl-p-aminophenol, is a widely used over-the-counter analgesic (pain reliever) and antipyretic (fever reducer). Paracetamol is classified as a mild analgesic. It is commonly used for the relief of headaches and other minor aches and pains and is a major ingredient in numerous cold and flu remedies. In combination with opioid analgesics, paracetamol can also be used in the management of more severe pain such as post-surgical pain and providing palliative care in advanced cancer patients. Though acetaminophen is used to treat inflammatory pain, it is not generally classified as an NSAID because it exhibits only weak anti-inflammatory activity. The onset of analgesia is approximately 11-29.5 minutes after oral administration of paracetamol, and its half-life is 1–4 hours. While generally safe for use at recommended doses ( and up to for adults), acute overdoses of paracetamol can cause potentially fatal kidney][, brain][ and liver damage and, in rare individuals, a normal dose can do the same. The risk may be heightened by chronic alcohol abuse; ethanol increases the number of CYP2E1 enzymes, a cytochrome P450 enzyme that leads to toxic byproducts of acetaminophen. Paracetamol toxicity is the foremost cause of acute liver failure in the Western world, and accounts for most drug overdoses in the United States, the United Kingdom, Australia and New Zealand. It is the active metabolite of the coal tar–derived phenacetin, once popular as an analgesic and antipyretic in its own right. However, unlike phenacetin and its combinations, paracetamol is not considered carcinogenic at therapeutic doses. The words acetaminophen (used in the United States, Canada, Japan, South Korea, Hong Kong, and Iran) and paracetamol (used elsewhere) both come from a chemical name for the compound: para-acetylaminophenol and para-acetylaminophenol. In some contexts, it is simply abbreviated as APAP, for acetyl-para-aminophenol. Paracetamol is approved for reducing fever in people of all ages. The World Health Organization (WHO) recommends that paracetamol only be used to treat fever in children if their temperature is greater than . The efficacy of paracetamol by itself in children with fevers has been questioned and a meta-analysis showed that it is less effective than ibuprofen. Paracetamol is used for the relief of pains associated with many parts of the body. It has analgesic properties comparable to those of aspirin, while its anti-inflammatory effects are weaker. It is better tolerated than aspirin in patients in whom excessive gastric acid secretion or prolongation of bleeding time may be a concern. Available without a prescription, it has in recent][ years increasingly become a common household drug. Paracetamol can relieve pain in mild arthritis][ but has no effect on the underlying inflammation, redness, and swelling of the joint. It is as effective as the non-steroidal anti-inflammatory drug (NSAID) ibuprofen in relieving the pain of osteoarthritis of the knee.][ Paracetamol has relatively little anti-inflammatory activity, unlike other common analgesics such as the NSAIDs aspirin and ibuprofen. But research studies analysis showed that ibuprofen and paracetamol have similar effects in the treatment of headache. Regarding comparative efficacy, studies show conflicting results when compared to NSAIDs. A randomized controlled trial of chronic pain from osteoarthritis in adults found similar benefit from paracetamol and ibuprofen. The efficacy of paracetamol when used in a combination form with weak opioids (such as codeine) has been questioned by recent][ data studies; the small amount of data available have made reaching a conclusion difficult. Combination drugs of paracetamol and strong opioids like morphine have been shown][ to reduce the amount of opioid used and improve analgesic effect as well as discouraging overuse of addictive opioids due to APAP's toxic effects, as it depletes glutathione and thus exacerbates disease in general. A randomized controlled trial of acute musculoskeletal pain in children found that the standard over-the-counter dose of ibuprofen gives greater pain relief than the standard dose of paracetamol. Paracetamol acts on, and suppresses pain through, the central nervous system rather than the peripheral nervous system. Recent research suggests that it deadens the neural response that causes the pain of social rejection as well as neural responses related to physical pain. Paracetamol is metabolized by the liver and is hepatotoxic; side effects are multiplied when combined with alcoholic drinks, and very likely in chronic alcoholics or patients with liver damage. Prolonged daily use increases the risk of upper gastrointestinal complications such as stomach bleeding, and may cause kidney or liver damage. And chronic users of paracetamol may have a higher risk of developing blood cancer. However in recommended doses and for a limited course of treatment, the side effects of paracetamol are mild to non-existent. In contrast to aspirin, paracetamol is not an antithrombotic, and thus may be used in patients where coagulation is a concern, and it does not cause gastric irritation. However, paracetamol does not help reduce inflammation, while aspirin does. Compared to ibuprofen—whose side effects may include diarrhea, vomiting and abdominal pain—paracetamol has fewer adverse gastrointestinal effects. Until 2010, paracetamol was believed safe in pregnancy (as it does not affect the closure of the fetal ductus arteriosus as NSAIDs can). However, in a study published in October 2010 it has been linked to infertility in the adult life of the unborn. Unlike aspirin, it is safe for children, as paracetamol is not associated with a risk of Reye's syndrome in children with viral illnesses. In one study, paracetamol use for fever in the first year of life was associated with a moderate increase in the incidence of asthmatic symptoms at 6–7 years, and that paracetamol use, both in the first year of life and in children aged 6–7 years, was associated with a moderate increased incidence of rhinoconjunctivitis and eczema. Untreated paracetamol overdose results in a lengthy, painful illness. Signs and symptoms of paracetamol toxicity may initially be absent or non-specific symptoms. The first symptoms of overdose usually begin several hours after ingestion, with nausea, vomiting, sweating, and pain as acute liver failure starts. People who take overdoses of paracetamol do not lose consciousness, although most people who use paracetamol wrongly believe that they will be rendered unconscious by the drug. The process of dying from an overdose usually takes three to five days. Paracetamol hepatotoxicity is, by far, the most common cause of acute liver failure in both the United States and the United Kingdom. Toxicity of paracetamol arises often due to its quinone metabolite. Paracetamol overdose results in more calls to poison control centers in the US than overdose of any other pharmacological substance. Untreated overdose can lead to liver failure and death within days. Treatment is aimed at removing the paracetamol from the body and replacing glutathione. Activated charcoal can be used to decrease absorption of paracetamol if the patient presents for treatment soon after the overdose. While the antidote, acetylcysteine, (also called N-acetylcysteine or NAC) acts as a precursor for glutathione, helping the body regenerate enough to prevent damage to the liver, a liver transplant is often required if damage to the liver becomes severe. N-Acetylcysteine also helps in neutralizing the imidoquinone metabolite of acetaminophen. Renal failure is also a possible side effect. There are tablets available (brand-name in the UK Paradote) that combine paracetamol with an antidote (methionine), to protect the liver in case of an overdose. In June 2009, a U.S. Food and Drug Administration (FDA) advisory committee recommended that new restrictions should be placed on paracetamol usage in the United States to help protect people from the potential toxic effects. The maximum dosage at any given time would be decreased from 1000 mg to 650 mg, while combinations of paracetamol and narcotic analgesics would be prohibited. Committee members were particularly concerned by the fact that the present maximum dosages of paracetamol had been shown to produce alterations in hepatic function. In January 2011, the FDA asked manufacturers of prescription combination products containing paracetamol to limit the amount of paracetamol to no more than 325 mg per tablet or capsule and began requiring manufacturers to update the labels of all prescription combination paracetamol products to warn of the potential risk for severe liver damage. Manufacturers will have three years to limit the amount of paracetamol in their prescription drug products to 325 mg per dosage unit. In November 2011, the Medicines and Healthcare products Regulatory Agency revised UK dosing of liquid paracetamol for children. Paracetamol is part of the class of drugs known as "aniline analgesics"; it is the only such drug still in use today. It is not considered an NSAID because it does not exhibit significant anti-inflammatory activity (it is a weak COX inhibitor). This is despite the evidence that paracetamol and NSAIDs have some similar pharmacological activity. To date, the mechanism of action of paracetamol is not completely understood. The main mechanism proposed is the inhibition of cyclooxygenase (COX), and recent findings suggest that it is highly selective for COX-2. While it has analgesic and antipyretic properties comparable to those of aspirin or other NSAIDs, its peripheral anti-inflammatory activity is usually limited by several factors, one of which is the high level of peroxides present in inflammatory lesions. However, in some circumstances, even peripheral anti-inflammatory activity comparable to NSAIDs can be observed. An article in Nature Communications from researchers in London, UK and Lund, Sweden in November 2011 has found a hint to the analgesic mechanism of paracetamol (acetaminophen), being that the metabolites of paracetamol e.g. NAPQI, act on TRPA1-receptors in the spinal cord to suppress the signal transduction from the superficial layers of the dorsal horn, to alleviate pain. This conclusion has been contested in a new hypothesis paper on how paracetamol might act. The author concedes that NAPQI is the active metabolite but that this reactive compound should react not only with the thiol in TRPA1 but also with any other suitably available nucleophile that it happens to encounter. It is suggested that thiol groups in cysteine proteases, e.g. the proteases that take part in the processing of procytokines, such as those generating IL-1β and IL-6, might be the targets giving rise to overall analgesic effects. Because of its selectivity for COX-2 it does not significantly inhibit the production of the pro-clotting thromboxanes. The COX family of enzymes are responsible for the metabolism of arachidonic acid to 2prostaglandin H, an unstable molecule that is, in turn, converted to numerous other pro-inflammatory compounds. Classical anti-inflammatories such as the NSAIDs block this step. Only when appropriately oxidized is the COX enzyme highly active. Paracetamol reduces the oxidized form of the COX enzyme, preventing it from forming pro-inflammatory chemicals. This leads to a reduced amount of prostaglandin E2 in the CNS, thus lowering the hypothalamic set-point in the thermoregulatory centre. Paracetamol also modulates the endogenous cannabinoid system. Paracetamol is metabolized to AM404, a compound with several actions; what is most important is that it inhibits the reuptake of the endogenous cannabinoid/vanilloid anandamide by neurons. Anandamide reuptake would result in lower synaptic levels and less activation of the main pain receptor (nociceptor) of the body, the TRPV1 (older name: vanilloid receptor). By inhibiting anandamide reuptake, levels in the synapse remain high and are able to desensitize the TRPV1 receptor much like capsaicin. Furthermore, AM404 inhibits sodium channels, as do the anesthetics lidocaine and procaine. Either of these actions by themselves has been shown to reduce pain, and are a possible mechanism for paracetamol. However, it has been demonstrated that, after blocking cannabinoid receptors with synthetic antagonists, paracetamol's analgesic effects are prevented, suggesting its pain-relieving action involves the endogenous cannabinoid system. Spinal TRPA1 receptors have also been demonstrated to mediate antinociceptive effects of paracetamol and Δ9-tetrahydrocannabinol in mice. Aspirin is known to inhibit the cyclooxygenase (COX) family of enzymes and, because paracetamol's action is partially similar to aspirin's,][ much research has focused on whether paracetamol also inhibits COX. It is now clear that paracetamol acts via at least two pathways. The exact mechanisms by which COX is inhibited in various circumstances are still a subject of discussion. Because of differences in the activity of paracetamol, aspirin, and other NSAIDs, it has been postulated that further COX variants may exist. One theory holds that paracetamol works by inhibiting the COX-3 isoform - a COX-1 splice variant - of the COX family of enzymes. When expressed in dogs, this enzyme shares a strong similarity to the other COX enzymes, produces pro-inflammatory chemicals, and is selectively inhibited by paracetamol. However, some research has suggested that, in humans and mice, the COX-3 enzyme is without inflammatory action and paracetamol's blockage of it is not significant in its functioning in humans. Another possibility is that paracetamol blocks cyclooxygenase (as in aspirin), but that, in an inflammatory environment where the concentration of peroxides is high, the high oxidation state of paracetamol prevents its actions. This idea would mean that paracetamol has no direct effect at the site of inflammation, but instead acts in the CNS where the environment is not oxidative, to reduce temperature, etc. The exact mechanism by which paracetamol is believed to affect COX-3 is disputed. Paracetamol's increase of social behavior in mice (which corresponds to its reduction of social rejection response in humans) does not appear to be due to cannabinoid receptor type 1 activity. It may result from serotonin receptor agonism. Paracetamol consists of a benzene ring core, substituted by one hydroxyl group and the nitrogen atom of an amide group in the para (1,4) pattern. The amide group is acetamide (ethanamide). It is an extensively conjugated system, as the lone pair on the hydroxyl oxygen, the benzene pi cloud, the nitrogen lone pair, the p orbital on the carbonyl carbon, and the lone pair on the carbonyl oxygen are all conjugated. The presence of two activating groups also make the benzene ring highly reactive toward electrophilic aromatic substitution. As the substituents are ortho, para-directing and para with respect to each other, all positions on the ring are more or less equally activated. The conjugation also greatly reduces the basicity of the oxygens and the nitrogen, while making the hydroxyl acidic through delocalisation of charge developed on the phenoxide anion. In the laboratory, paracetamol is easily prepared by nitrating phenol with sodium nitrate, separating the desired para- nitrophenol from the ortho- byproduct, and reducing the nitro group with sodium borohydride. The resultant -aminophenol4 is then acetylated with acetic anhydride. In this reaction, phenol is strongly activating, thus the reaction requires only mild conditions (cf. the nitration of benzene). The industrial process is analogous, but hydrogenation is used instead of the sodium borohydride reduction. A simpler synthesis by Hoechst-Celanese involves direct acylation of phenol with acetic anhydride catalyzed by HF, conversion of the ketone to a ketoxime with hydroxylamine, followed by the acid-catalyzed Beckmann rearrangement to give the amide. Demand for paracetamol in the United States was estimated at 30–35 thousand tonnes per year in 1997, equal to the demand from the rest of the world. Paracetamol is metabolised primarily in the liver, into toxic and non-toxic products. Three metabolic pathways are notable: All three pathways yield final products that are inactive, non-toxic, and eventually excreted by the kidneys. In the third pathway, however, the intermediate product NAPQI is toxic. NAPQI is primarily responsible for the toxic effects of paracetamol; this constitutes an example of toxication. Production of NAPQI is due primarily to two isoenzymes of cytochrome P450: CYP2E1 and CYP1A2. The P450 gene is highly polymorphic, however, and individual differences in paracetamol toxicity are believed due to a third isoenzyme, CYP2D6. Genetic polymorphisms in CYP2D6 may contribute to significantly different rates of production of NAPQI. Furthermore, individuals can be classified as "extensive", "ultrarapid", "intermediate" and "poor" metabolizers (producers of NAPQI), depending on their levels of CYP2D6 expression. Although CYP2D6 metabolises paracetamol into NAPQI to a lesser extent than other P450 enzymes, its activity may contribute to paracetamol toxicity in extensive and ultrarapid metabolisers, and when paracetamol is taken at very large doses. At usual doses, NAPQI is quickly detoxified by conjugation with glutathione. Following overdose, and possibly also in extensive and ultrarapid metabolizers, this detoxification pathway becomes saturated, and, as a consequence, NAPQI accumulates causing liver and renal toxicity. -Aminophenol4 may be obtained by the amide hydrolysis of paracetamol. 4-Aminophenol prepared this way, and related to the commercially available Metol, has been used as a developer in photography by hobbyists. This reaction is also used to determine paracetamol in urine samples: After hydrolysis with hydrochloric acid, 4-aminophenol reacts in ammonia solution with a phenol derivate, e.g. salicylic acid, to form an indophenol dye under oxidization by air. Acetanilide was the first aniline derivative serendipitously found to possess analgesic as well as antipyretic properties, and was quickly introduced into medical practice under the name of Antifebrin by A. Cahn and P. Hepp in 1886. But its unacceptable toxic effects, the most alarming being cyanosis due to methemoglobinemia, prompted the search for less toxic aniline derivatives. Harmon Northrop Morse had already synthesized paracetamol at Johns Hopkins University via the reduction of -nitrophenolp with tin in glacial acetic acid in 1877, but it was not until 1887 that clinical pharmacologist Joseph von Mering tried paracetamol on patients. In 1893, von Mering published a paper reporting on the clinical results of paracetamol with phenacetin, another aniline derivative. Von Mering claimed that, unlike phenacetin, paracetamol had a slight tendency to produce methemoglobinemia. Paracetamol was then quickly discarded in favor of phenacetin. The sales of phenacetin established Bayer as a leading pharmaceutical company. Overshadowed in part by aspirin, introduced into medicine by Heinrich Dreser in 1899, phenacetin was popular for many decades, particularly in widely advertised over-the-counter "headache mixtures", usually containing phenacetin, an aminopyrine derivative of aspirin, caffeine, and sometimes a barbiturate. Von Mering's claims remained essentially unchallenged for half a century, until two teams of researchers from the United States analyzed the metabolism of acetanilide and paracetamol. In 1947 David Lester and Leon Greenberg found strong evidence that paracetamol was a major metabolite of acetanilide in human blood, and in a subsequent study they reported that large doses of paracetamol given to albino rats did not cause methemoglobinemia. In three papers published in the September 1948 issue of the Journal of Pharmacology and Experimental Therapeutics, Bernard Brodie, Julius Axelrod and Frederick Flinn confirmed using more specific methods that paracetamol was the major metabolite of acetanilide in human blood, and established that it was just as efficacious an analgesic as its precursor. They also suggested that methemoglobinemia is produced in humans mainly by another metabolite, phenylhydroxylamine. A follow-up paper by Brodie and Axelrod in 1949 established that phenacetin was also metabolized to paracetamol. This led to a "rediscovery" of paracetamol. It has been suggested that contamination of paracetamol with 4-aminophenol, the substance von Mering synthesized it from, may be the cause for his spurious findings. Paracetamol was first marketed in the United States in 1953 by Sterling-Winthrop Co., which promoted it as preferable to aspirin since it was safe to take for children and people with ulcers. The best known brand today for paracetamol in the United States, Tylenol, was established in 1955 when McNeil Laboratories started selling paracetamol as a pain and fever reliever for children, under the brand name Tylenol Children's Elixir—the word "tylenol" was a contraction of para-acetylaminophenol. In 1956, 500 mg tablets of paracetamol went on sale in the United Kingdom under the trade name Panadol, produced by Frederick Stearns & Co, a subsidiary of Sterling Drug Inc. Panadol was originally available only by prescription, for the relief of pain and fever, and was advertised as being "gentle to the stomach," since other analgesic agents of the time contained aspirin, a known stomach irritant. In 1963, paracetamol was added to the British Pharmacopoeia, and has gained popularity since then as an analgesic agent with few side-effects and little interaction with other pharmaceutical agents. Concerns about paracetamol's safety delayed its widespread acceptance until the 1970s, but in the 1980s paracetamol sales exceeded those of aspirin in many countries, including the United Kingdom. This was accompanied by the commercial demise of phenacetin, blamed as the cause of analgesic nephropathy and hematological toxicity. The U.S. patent on paracetamol has long expired, and generic versions of the drug are widely available under the Drug Price Competition and Patent Term Restoration Act of 1984, although certain Tylenol preparations were protected until 2007. U.S. patent 6,126,967 filed September 3, 1998 was granted for "Extended release acetaminophen particles". Paracetamol is available in a tablet, capsule, liquid suspension, suppository, intravenous, and intramuscular form. The common adult dose is 500 mg to 1000 mg. The recommended maximum daily dose, for adults, is 4000 mg. In recommended doses, paracetamol is generally safe for children and infants, as well as for adults, although rare cases of acute liver injury have been linked to amounts lower than 2500 mg per day. Panadol, which is marketed in Africa, Asia, Europe, Central America, and Australasia, is the most widely available brand of paracetamol, sold in over 80 countries. In North America, paracetamol is sold in generic form (usually labeled as acetaminophen) or under a number of trade names, for instance, Tylenol (McNeil-PPC, Inc.), Anacin-3, Tempra, Datril, and Ofirmev. While there is brand named paracetamol available in the UK (e.g. Panadol), unbranded or generic paracetamol is more commonly sold. Acamol, a brand name for paracetamol produced by Teva Pharmaceutical Industries in Israel, is one of the most widely used drugs in that country. In the Philippines, the largest-selling paracetamol brand is Biogesic, manufactured by the drug giant United Laboratories. Biogesic tablet sales reach nearly a billion units each year in the country alone, not including liquid suspension formats. The brand is also available in most of the ASEAN countries where the drug giant has market presence. In Europe, the most common brands of paracetamol are Efferalgan and Doliprane. In India, the most common brand of paracetamol is Crocin manufactured by Glaxo SmithKline Asia. In Bangladesh the most popular two brand are Napa and Renova manufactured by Beximco Pharma and Opsonin Pharma respectively. In China paracetamol is sold over the counter as Duìyǐxiān'ānjīfēn Piàn (对乙酰氨基酚片). Likewise in Japan it is sold under the name Acetaminophen (アセトアミノフェン Asetoaminofen). In North Korea the DPRK-Swiss joint venture PyongSu Pharma markets the drug as PyongSu Cetamol. In some formulations, paracetamol is combined with the opioid codeine, sometimes referred to as co-codamol (BAN). In the United States and Canada, this is marketed under the name of Tylenol #1/2/3/4, which contain 8–10 mg, 15 mg, 30 mg, and 60 mg of codeine, respectively. In the U.S., this combination is available only by prescription, while the lowest-strength preparation is over-the-counter in Canada, and, in other countries, other strengths may be available over the counter. There are generic forms of these combinations as well. In the UK and in many other countries, this combination is marketed under the names of Tylex CD and Panadeine. Other names include Captin, Disprol, Dymadon, Fensum, Hedex, Mexalen, Nofedol, Panocod, Paralen, Pediapirin, Perfalgan, and Solpadeine. Paracetamol is also combined with other opioids such as dihydrocodeine, referred to as co-dydramol (BAN), oxycodone or hydrocodone, marketed in the U.S. as Percocet and Vicodin, respectively. Another very commonly used analgesic combination includes paracetamol in combination with propoxyphene napsylate, sold under the brand name Darvocet. A combination of paracetamol, codeine, and the calmative doxylamine succinate is marketed as Syndol or Mersyndol. The efficacy of paracetamol/codeine combinations have been questioned by recent research. Paracetamol is commonly used in multi-ingredient preparations for migraine headache, typically including butalbital and paracetamol with or without caffeine, and sometimes containing codeine. Paracetamol is extremely toxic to cats, which lack the necessary glucuronyl transferase enzymes to safely break it down. Initial symptoms include vomiting, salivation, and discolouration of the tongue and gums. Unlike an overdose in humans, liver damage is rarely the cause of death; instead, methemoglobin formation and the production of Heinz bodies in red blood cells inhibit oxygen transport by the blood, causing asphyxiation (methemoglobemia and hemolytic anemia). Treatment with N-acetylcysteine, methylene blue or both is sometimes effective after the ingestion of small doses of paracetamol. Although paracetamol is believed to have no significant anti-inflammatory activity, it has been reported as effective as aspirin in the treatment of musculoskeletal pain in dogs. A paracetamol-codeine product (trade name Pardale-V) licensed for use in dogs is available on veterinary prescription in the UK. It should be administered to dogs only on veterinary advice and with extreme caution. The main effect of toxicity in dogs is liver damage, GI ulceration has been reported. N-acetylcysteine treatment is efficacious in dogs when administered within a 2 hours of paracetamol ingestion. Paracetamol is also lethal to snakes, and has been suggested as a chemical control program for the invasive brown tree snake (Boiga irregularis) in Guam. Doses of 80 mg are inserted into dead mice scattered by helicopter.
M: CNS anat (n/s/m/p/4/e/b/d/c/a/f/l/g)/phys/devp noco (m/d/e/h/v/s)/cong/tumr, sysi/epon, injr proc, drug (N1A/2AB/C/3/4/7A/B/C/D)
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