Clinical data | |
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Trade names | Ketogan |
Other names | Ketobemidone, Cliradon, Cymidon, Ketogan, Ketorax |
AHFS/Drugs.com | International Drug Names |
Routes of administration | By mouth, rectal, intravenous |
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Pharmacokinetic data | |
Bioavailability | 34~40% (oral), 44% (rectal) |
Elimination half-life | 2–4 hours |
Duration of action | 3–5 hours |
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DrugBank | |
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ChEMBL | |
CompTox Dashboard (EPA) | |
ECHA InfoCard | 100.006.748 |
Chemical and physical data | |
Formula | C15H21NO2 |
Molar mass | 247.338 g·mol−1 |
3D model (JSmol) | |
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Ketobemidone, sold under the brand name Ketogan among others, is a powerful synthetic opioid painkiller. Its effectiveness against pain is in the same range as morphine, and it also has some NMDA-antagonist properties imparted, in part, by its metabolite norketobemidone. [2] This may make it useful for some types of pain that do not respond well to other opioids. [2] It is marketed in Denmark, Iceland, Norway. Until 2024 it was availble in, but is now withdrawn in Sweden. It is used for severe pain. [3]
Ketobemidone was first synthesized in 1942 by Eisleb and colleagues, [4] at the laboratory of I.G. Farbenindustrie at Hoechst during the Second World War. The first study of it in humans was published in 1946, [5] and it was introduced in clinical medicine shortly after. It was not in clinical use in the United States when the Controlled Substances Act 1970 was promulgated and was assigned to Schedule I with an ACSCN of 9628. As of 2013, no annual manufacturing quota was assigned by the DEA. [6]
Pfizer manufactures ketobemidone under the tradenames Ketogan and Ketorax. It is available as tablets, suppositories, and injection fluid. A sustained release formulation, sold as Ketodur, exists in some countries and contains 10 or 25 mg ketobemidone.
Experiments on former addicts indicated it was quite addictive and in high doses, compared to other opioids, may have increased abuse potential in former and current opioid addicts. While some effort was first suggested for drafting of a resolution urging governments to stop manufacture and use of ketobemidone, [7] this result was not in agreement with clinical observations, and another study in 1958 did not find it more addictive than morphine. That study noticed that while for morphine the dose for euphoria is the same as that for analgesia, for ketobemidone the analgesic dose was well below the euphoric dose. Thus, even compared to morphine, ketobemidone may be much more effective without causing significant euphoria and thus having a lower risk of addiction under the supervision of a qualified clinician. [8] Ketobemidone is mostly used in the Scandinavian countries, with Denmark topping the statistics. [9]
Analgesia after 5-10 mg orally or 5–7.5 mg intravenously lasts 3–5 hours. Ketobemidone is also available in preparations with a spasmolytic, which can improve the analgesia.
Ketobemidone is mainly metabolized by conjugation of the phenolic hydroxyl group, and by N-demethylation. Only about 13-24% is excreted unchanged after intravenous administration. [10]
Ketobemidone is 1-methyl-4-(3-hydroxyphenyl)-4-propionylpiperidine. It is usually available as the hydrochloride, which is a white powder. It is synthesized by alkylating (3-methoxyphenyl)acetonitrile with bis(2-chloroethyl)methylamine, followed by reaction with ethylmagnesium bromide, and finally O-demethylation with hydrobromic acid. [11]
Because of a strong vesicant nature of bis(2-chloroethyl)methylamine there are many other routes developed for obtaining ketobemidone. A route depicted below lays through first alkylating the same (3-methoxyphenyl)acetonitrile with 2-chloro-N,N-dimethylethylamine or 2-chloro-N-benzyl-N-methylethylamine. [12] Next, those amines are alkylated once again using a mixed 1-bromo-2-chloroethane, thus completing the piperidine ring and obtaining a quaternary ammonium salt, which can be dequaternized using thiophenol salt [13] (for N,N-dimethylammonium) or catalytic hydrogenation [14] (for both compounds) to a common 4-(3-methoxyphenyl)-4-cyano-1-methyl-pyperidine. The latter yields ketobemidone after Grignard reaction with ethylmagnesium bromide and ether cleavage.
Morphine, formerly also called morphia, is an opiate that is found naturally in opium, a dark brown resin produced by drying the latex of opium poppies. It is mainly used as an analgesic. There are numerous methods used to administer morphine: oral; sublingual; via inhalation; injection into a muscle, injection under the skin, or injection into the spinal cord area; transdermal; or via rectal suppository. It acts directly on the central nervous system (CNS) to induce analgesia and alter perception and emotional response to pain. Physical and psychological dependence and tolerance may develop with repeated administration. It can be taken for both acute pain and chronic pain and is frequently used for pain from myocardial infarction, kidney stones, and during labor. Its maximum effect is reached after about 20 minutes when administered intravenously and 60 minutes when administered by mouth, while the duration of its effect is 3–7 hours. Long-acting formulations of morphine are sold under the brand names MS Contin and Kadian, among others. Generic long-acting formulations are also available.
Oxycodone, sold under the brand name Roxicodone and OxyContin among others, is a semi-synthetic opioid used medically for treatment of moderate to severe pain. It is highly addictive and is a commonly abused drug. It is usually taken by mouth, and is available in immediate-release and controlled-release formulations. Onset of pain relief typically begins within fifteen minutes and lasts for up to six hours with the immediate-release formulation. In the United Kingdom, it is available by injection. Combination products are also available with paracetamol (acetaminophen), ibuprofen, naloxone, naltrexone, and aspirin.
Hydromorphone, also known as dihydromorphinone, and sold under the brand name Dilaudid among others, is a morphinan opioid used to treat moderate to severe pain. Typically, long-term use is only recommended for pain due to cancer. It may be used by mouth or by injection into a vein, muscle, or under the skin. Effects generally begin within half an hour and last for up to five hours. A 2016 Cochrane review found little difference in benefit between hydromorphone and other opioids for cancer pain.
Remifentanil, marketed under the brand name Ultiva is a potent, short-acting synthetic opioid analgesic drug. It is given to patients during surgery to relieve pain and as an adjunct to an anaesthetic. Remifentanil is used for sedation as well as combined with other medications for use in general anesthesia. The use of remifentanil has made possible the use of high-dose opioid and low-dose hypnotic anesthesia, due to synergism between remifentanil and various hypnotic drugs and volatile anesthetics.
Nalbuphine, sold under the brand names Nubain among others, is an opioid analgesic which is used in the treatment of pain. It is given by injection into a vein, muscle, or fat.
Dihydromorphine is a semi-synthetic opioid structurally related to and derived from morphine. The 7,8-double bond in morphine is reduced to a single bond to get dihydromorphine. Dihydromorphine is a moderately strong analgesic and is used clinically in the treatment of pain and also is an active metabolite of the analgesic opioid drug dihydrocodeine. Dihydromorphine occurs in trace quantities in assays of opium on occasion, as does dihydrocodeine, dihydrothebaine, tetrahydrothebaine, etc. The process for manufacturing dihydromorphine from morphine for pharmaceutical use was developed in Germany in the late 19th century, with the synthesis being published in 1900 and the drug introduced clinically as Paramorfan shortly thereafter. A high-yield synthesis from tetrahydrothebaine was later developed.
Levorphanol is an opioid medication used to treat moderate to severe pain. It is the levorotatory enantiomer of the compound racemorphan. Its dextrorotatory counterpart is dextrorphan.
Piritramide(R-3365, trade names Dipidolor, Piridolan, Pirium and others) is a synthetic opioid analgesic that is marketed in certain European countries including: Austria, Belgium, Czech Republic, Slovenia, Germany and the Netherlands. It comes in free form, is about 0.75x times as potent as morphine and is given parenterally for the treatment of severe pain. Nausea, vomiting, respiratory depression and constipation are believed to be less frequent with piritramide than with morphine, and it produces more rapid-onset analgesia when compared to morphine and pethidine. After intravenous administration the onset of analgesia is as little as 1–2 minutes, which may be related to its great lipophilicity. The analgesic and sedative effects of piritramide are believed to be potentiated with phenothiazines and its emetic (nausea/vomiting-inducing) effects are suppressed. The volume of distribution is 0.7-1 L/kg after a single dose, 4.7-6 L/kg after steady-state concentrations are achieved and up to 11.1 L/kg after prolonged dosing.
Nicomorphine is the 3,6-dinicotinate ester of morphine. It is a strong opioid agonist analgesic two to three times as potent as morphine with a side effect profile similar to that of dihydromorphine, morphine, and diamorphine.
Codeine is an opiate and prodrug of morphine mainly used to treat pain, coughing, and diarrhea. It is also commonly used as a recreational drug. It is found naturally in the sap of the opium poppy, Papaver somniferum. It is typically used to treat mild to moderate degrees of pain. Greater benefit may occur when combined with paracetamol (acetaminophen) or a nonsteroidal anti-inflammatory drug (NSAID) such as aspirin or ibuprofen. Evidence does not support its use for acute cough suppression in children. In Europe, it is not recommended as a cough medicine in those under 12 years of age. It is generally taken by mouth. It typically starts working after half an hour, with maximum effect at two hours. Its effects last for about four to six hours. Codeine exhibits abuse potential similar to other opioid medications, including a risk of addiction and overdose.
Phenadoxone is an opioid analgesic of the open chain class invented in Germany by Hoechst in 1947. It is one of a handful of useful synthetic analgesics which were used in the United States for various lengths of time in the 20 or so years after the end of the Second World War but which were withdrawn from the market for various or no known reason and which now are mostly in Schedule I of the United States' Controlled Substances Act of 1970, or in Schedule II but not produced or marketed in the US. Others on this list are ketobemidone (Ketogin), dextromoramide, phenazocine, dipipanone, piminodine (Alvodine), propiram (Algeril), anileridine (Leritine) and alphaprodine (Nisentil).
Hydroxypethidine (Bemidone) is an opioid analgesic that is an analogue of the more commonly used pethidine (meperidine). Hydroxypethidine is slightly more potent than meperidine as an analgesic, 1.5x meperidine in potency, and it also has NMDA antagonist properties like its close relative ketobemidone.
Oripavine is an opioid and the major metabolite of thebaine. It is the parent compound from which a series of semi-synthetic opioids are derived, which includes the compounds etorphine and buprenorphine. Although its analgesic potency is comparable to morphine, it is not used clinically due to its severe toxicity and low therapeutic index. Being a precursor to a series of extremely strong opioids, oripavine is a controlled substance in some jurisdictions.
Prodine is an opioid analgesic that is an analog of pethidine (meperidine). It was developed in Germany in the late 1940s.
Piminodine (Alvodine) is an opioid analgesic that is an analogue of pethidine (meperidine). It was used in medicine briefly during the 1960s and 70s, but has largely fallen out of clinical use. It was used particularly for obstetric analgesia and in dental procedures and, like pethidine, could be combined with hydroxyzine to intensify the effects. The duration of action is 2–4 hours; 7.5–10 mg via the subcutaneous route is the most common starting dose, being equal to 80–100 mg of pethidine, 40–60 mg of alphaprodine and 10 mg of morphine. Oral formulations were also available.
Propiram is a partial μ-opioid receptor agonist and weak μ antagonist analgesic from the ampromide family of drugs related to other drugs such as phenampromide and diampromide. It was invented in 1963 in the United Kingdom by Bayer but was not widely marketed, although it saw some limited clinical use, especially in dentistry. Propiram reached Phase III clinical trials in the United States and Canada.
Phenampromide is an opioid analgesic from the ampromide family of drugs, related to other drugs such as propiram and diampromide. It was invented in the 1960s by American Cyanamid Co. Although never given a general release, it was trialled and 50 mg codeine ≈ 60 mg phenampromide. Tests on the 2 isomers showed that all of the analgesic effects were caused by the (S) isomer. Introduction of a phenyl group to the 4-position of the piperidine-ring produces a drug 60-fold more potent than morphine. The most potent reported derivative is 4-hydroxy-4-phenyl phenapromide which displays analgesic activity some x150 greater than morphine.
An equianalgesic chart is a conversion chart that lists equivalent doses of analgesics. Equianalgesic charts are used for calculation of an equivalent dose between different analgesics. Tables of this general type are also available for NSAIDs, benzodiazepines, depressants, stimulants, anticholinergics and others.
Bucinnazine is an opioid analgesic drug that was widely used in China to treat pain in cancer patients as of 1986. It is one of the most potent compounds among a series of piperazine-amides first synthesized and reported in Japan in the 1970s. Bucinnazine has analgesic potency comparable to that of morphine, but with a relatively higher therapeutic index.
RB-120 is an orally active analog of the drug RB-101. It acts as an enkephalinase inhibitor, which is used in scientific research. Via intravenous administration, it is approximately three times as potent as RB-101 or twice as potent as the isolated (S,S) isomer of RB101. However, via i.p. administration it is approximately twice as potent as racemic RB-101 and about as potent as the isolated (S,S) isomer of RB101. During i.v. administration RB120 is approximately twice as weak as morphine in terms of analgesia; however, it is 16x weaker during i.p. and p.o. administration.
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