Oxazepam

Oxazepam
Clinical data
Routes of
administration		 Oral
ATC code N05BA04 (WHO)
Legal status
Legal status
Pharmacokinetic data
Bioavailability 95.5%
Metabolism Hepatic
Biological half-life 5–15 h[1]
Excretion Renal
Identifiers
CAS Number 604-75-1
PubChem (CID) 4616
IUPHAR/BPS 7253
DrugBank DB00842 YesY
ChemSpider 4455 YesY
UNII 6GOW6DWN2A YesY
KEGG D00464 YesY
ChEBI CHEBI:7823 YesY
ChEMBL CHEMBL568 YesY
ECHA InfoCard 100.009.161
Chemical and physical data
Formula C15H11ClN2O2
Molar mass 286.71 g·mol−1
3D model (Jmol) Interactive image
Melting point 205 to 206 °C (401 to 403 °F)
  (verify)

Oxazepam is a short-to-intermediate-acting benzodiazepine.[3][4] Oxazepam is used for the treatment of anxiety and insomnia and in the control of symptoms of alcohol withdrawal.

It is a metabolite of diazepam, prazepam, and temazepam,[5] and has moderate amnesic, anxiolytic, anticonvulsant, hypnotic, sedative, and skeletal muscle relaxant properties compared to other benzodiazepines.[6] Oxazepam was initially patented and marketed in 1965.[7]

Medical uses

It is an intermediate-acting benzodiazepine with a slow onset of action,[8] so it is usually prescribed to individuals who have trouble staying asleep, rather than falling asleep. It is commonly prescribed for anxiety disorders with associated tension, irritability, and agitation. It is also prescribed for drug and alcohol withdrawal, and for anxiety associated with depression. Physicians may use oxazepam outside its approved indications to treat social phobia, post-traumatic stress disorder, insomnia, premenstrual syndrome, and other conditions.[9]

Usage

Oxazepam, along with diazepam, nitrazepam, and temazepam, were the four benzodiazepines listed on the pharmaceutical benefits scheme and represented 82% of the benzodiazepine prescriptions in Australia in 1990-1991.[10]

Side effects

The side effects of oxazepam are similar to those of other benzodiazepines, and may include dizziness, drowsiness, headache, memory impairment, paradoxical excitement, and anterograde amnesia, but does not affect transient global amnesia. Side effects due to rapid decrease in dose or abrupt withdrawal from oxazepam may include abdominal and muscle cramps, convulsions, depression, inability to fall asleep or stay asleep, sweating, tremors, or vomiting.[11]

Tolerance, dependence and withdrawal

Oxazepam, as with other benzodiazepine drugs, can cause tolerance, physical dependence, addiction, and benzodiazepine withdrawal syndrome. Withdrawal from oxazepam or other benzodiazepines often leads to withdrawal symptoms which are similar to those seen during alcohol and barbiturate withdrawal. The higher the dose and the longer the drug is taken, the greater the risk of experiencing unpleasant withdrawal symptoms. Withdrawal symptoms can occur, though, at standard dosages and also after short-term use. Benzodiazepine treatment should be discontinued as soon as possible by a slow and gradual dose reduction regimen.[12]

Contraindications

Oxazepam is contraindicated in myasthenia gravis, chronic obstructive pulmonary disease, and limited pulmonary reserve, as well as severe hepatic disease.

Special precautions

Benzodiazepines require special precautions if used in the elderly, during pregnancy, in children, alcohol- or drug-dependent individuals, and individuals with comorbid psychiatric disorders.[13] Benzodiazepines including oxazepam are lipophilic drugs and rapidly penetrate membranes, so rapidly crosses over into the placenta with significant uptake of the drug. Use of benzodiazepines in late pregnancy, especially high doses, may result in floppy infant syndrome.[14]

Pregnancy

Oxazepam when taken during late in pregnancy, the third trimester, causes a definite risk to the neonate including a severe benzodiazepine withdrawal syndrome including hypotonia, and reluctance to suck, to apnoeic spells, cyanosis, and impaired metabolic responses to cold stress. Floppy infant syndrome and sedation in the newborn may also occur. Symptoms of floppy infant syndrome and the neonatal benzodiazepine withdrawal syndrome have been reported to persist from hours to months after birth.[15]

Interactions

As oxazepam is an active metabolite of diazepam, an overlap in possible interactions is likely with other drugs or food, with exception of the pharmacokinetic CYP450 interactions (e.g. with cimetidine). Precautions and following the prescription are required when taking oxazepam (or other benzodiazepines) in combinations with antidepressant medication (SSRIs such as Prozac, Zoloft, and Paxil, or multiple reuptake inhibitors such as Wellbutrin, Cymbalta, or Effexor), potent painkillers (opioids, e.g. morphine, oxycodone or methadone). Concurrent use of these medicines (as well as other benzodiazepines) can interact in a way that is difficult to predict. Drinking alcohol when taking oxazepam is not recommended. Concomitant use of oxazepam and alcohol can lead to increased sedation, severe problems with coordination (ataxia), decreased muscle tone, and in severe cases or in predisposed patients, even to life-threatening intoxications with respiratory depression, coma, and collapse.

Overdose

Oxazepam is generally less toxic in overdose than other benzodiazepines.[16] Important factors which affect the severity of a benzodiazepine overdose include the dose ingested, the age of the patient, and health status prior to overdose. Benzodiazepine overdoses can be much more dangerous if a coingestion of other CNS depressants such as opiates or alcohol has occurred. Symptoms of an oxazepam overdose include:[17][18][19]

Pharmacology

Oxazepam is an intermediate-acting benzodiazepine of the 3-hydroxy family; it acts on benzodiazepine receptors, resulting in increased effect of GABA to the GABAA receptor which results in inhibitory effects on the central nervous system.[20][21] The half-life of oxazepam is four to 15 hours.[22] It has been shown to suppress cortisol levels.[23] Oxazepam is the most slowly absorbed and has the slowest onset of action of all the common benzodiazepines according to one British study.[24]

Oxazepam is an active metabolite formed during the breakdown of diazepam, nordazepam, and certain similar drugs. It may be safer than many other benzodiazepines in patients with impaired liver function because it does not require hepatic oxidation, but rather, it is simply metabolized by glucuronidation, so oxazepam is less likely to accumulate and cause adverse reactions in the elderly or people with liver disease. Oxazepam is similar to lorazepam in this respect. (1) Preferential storage of oxazepam occurs in some organs, including the heart of the neonate. Absorption by any administered route and the risk of accumulation is significantly increased in the neonate, and withdrawal of oxazepam during pregnancy and breast feeding is recommended, as oxazepam is excreted in breast milk.[25]

Chemistry

Oxazepam exists as a racemic mixture. [26] Early attempts to isolate enantiomers were unsuccessful; the corresponding acetate has been isolated as a single enantiomer. Given the different rates of epimerization that occur at different pH levels, it was determined that there would be no therapeutic benefit to the administration of a single enantiomer over the racemic mixture. [27]

Society and culture

Misuse

Oxazepam has the potential for misuse, defined as taking the drug to achieve a high, or continuing to take the drug in the long term against medical advice.[28] Benzodiazepines, including diazepam, oxazepam, nitrazepam, and flunitrazepam, accounted for the largest volume of forged drug prescriptions in Sweden from 1982 to 1986. During this time, a total of 52% of drug forgeries were for benzodiazepines, suggesting they were a major prescription drug class of abuse.[29]

However, due to its slow rate of absorption and its slow onset of action,[24] oxazepam has a relatively low potential for abuse compared to some other benzodiazepines, such as temazepam, flunitrazepam, or triazolam, which have a high potential for abuse similar to barbiturates.[30]

Oxazepam is a Schedule IV drug under the Convention on Psychotropic Substances.[31]

Brand names

It is marketed in English-speaking countries under the brand names Alepam, Bonare, Medopam, Murelax, Noripam, Opamox, Ox-Pam, Purata, Serax and Serepax, as Vaben in Israel, as Oxapax in Denmark, as Sobril and Alopam in Norway, as Sobril or Oxascand in Iceland and Sweden, Zaxpam in India, and Praxiten in Croatia. Marketed in French-speaking countries as Seresta.

References

  1. ↑ Greenblatt DJ (1981). "Clinical pharmacokinetics of oxazepam and lorazepam". Clin Pharmacokinet. 6 (2): 89–105. doi:10.2165/00003088-198106020-00001. PMID 6111408.
  2. ↑ CID 4616 from PubChem
  3. ↑ "Benzodiazepine Names". non-benzodiazepines.org.uk. Retrieved 2008-12-29.
  4. ↑ "FASS". Läkemedelsindustriföreningens Service AB. Retrieved 2011-02-03.
  5. ↑ "Oxazepam (IARC Summary & Evaluation, Volume 66, 1996)". IARC. Retrieved 2009-03-12.
  6. ↑ Mandrioli R, Mercolini L, Raggi MA (October 2008). "Benzodiazepine metabolism: an analytical perspective". Curr. Drug Metab. 9 (8): 827–44. doi:10.2174/138920008786049258. PMID 18855614.
  7. ↑ Shorter, Edward (2005). "B". A Historical Dictionary of Psychiatry. Oxford University Press. ISBN 9780190292010.
  8. ↑ Galanter, Marc; Kleber, Herbert D. (1 July 2008). The American Psychiatric Publishing Textbook of Substance Abuse Treatment (4th ed.). United States of America: American Psychiatric Publishing Inc. p. 216. ISBN 978-1-58562-276-4.
  9. ↑ http://www.psychatlanta.com/documents/serax.pdf
  10. ↑ Mant A; Whicker SD; McManus P; Birkett DJ; Edmonds D; Dumbrell D. (December 1993). "Benzodiazepine utilisation in Australia: report from a new pharmacoepidemiological database". Aust J Public Health. 17 (4): 345–9. doi:10.1111/j.1753-6405.1993.tb00167.x. PMID 7911332.
  11. ↑ Oxazepam patient advice including side effects
  12. ↑ MacKinnon GL; Parker WA. (1982). "Benzodiazepine withdrawal syndrome: a literature review and evaluation". The American Journal of Drug and Alcohol Abuse. 9 (1): 19–33. doi:10.3109/00952998209002608. PMID 6133446.
  13. ↑ Authier, N.; Balayssac, D.; Sautereau, M.; Zangarelli, A.; Courty, P.; Somogyi, AA.; Vennat, B.; Llorca, PM.; Eschalier, A. (November 2009). "Benzodiazepine dependence: focus on withdrawal syndrome". Ann Pharm Fr. 67 (6): 408–13. doi:10.1016/j.pharma.2009.07.001. PMID 19900604.
  14. ↑ Kanto JH. (May 1982). "Use of benzodiazepines during pregnancy, labour and lactation, with particular reference to pharmacokinetic considerations". Drugs. 23 (5): 354–80. doi:10.2165/00003495-198223050-00002. PMID 6124415.
  15. ↑ McElhatton PR. (Nov–Dec 1994). "The effects of benzodiazepine use during pregnancy and lactation". Reprod Toxicol. 8 (6): 461–75. doi:10.1016/0890-6238(94)90029-9. PMID 7881198.
  16. ↑ Buckley NA, Dawson AH, Whyte IM, O'Connell DL (28 January 1995). "Relative toxicity of benzodiazepines in overdose". BMJ. 310 (6974): 219–21. doi:10.1136/bmj.310.6974.219. PMC 2548618Freely accessible. PMID 7866122.
  17. ↑ Gaudreault P, Guay J, Thivierge RL, Verdy I (1991). "Benzodiazepine poisoning. Clinical and pharmacological considerations and treatment". Drug Saf. 6 (4): 247–65. doi:10.2165/00002018-199106040-00003. PMID 1888441.
  18. ↑ Perry HE, Shannon MW (June 1996). "Diagnosis and management of opioid- and benzodiazepine-induced comatose overdose in children". Current Opinion in Pediatrics. 8 (3): 243–7. doi:10.1097/00008480-199606000-00010. PMID 8814402.
  19. ↑ Busto U, Kaplan HL, Sellers EM (February 1980). "Benzodiazepine-associated emergencies in Toronto". Am J Psychiatry. 137 (2): 224–7. PMID 6101526.
  20. ↑ Skerritt JH; Johnston GA. (May 6, 1983). "Enhancement of GABA binding by benzodiazepines and related anxiolytics". Eur J Pharmacol. 89 (3–4): 193–8. doi:10.1016/0014-2999(83)90494-6. PMID 6135616.
  21. ↑ Oelschläger H. (July 4, 1989). "[Chemical and pharmacologic aspects of benzodiazepines]". Schweiz Rundsch Med Prax. 78 (27–28): 766–72. PMID 2570451.
  22. ↑ Professor heather Ashton (April 2007). "Benzodiazepine equivalency table". Retrieved September 23, 2007.
  23. ↑ Christensen P; Lolk A; Gram LF; Kragh-Sørensen P. (1992). "Benzodiazepine-induced sedation and cortisol suppression. A placebo-controlled comparison of oxazepam and nitrazepam in healthy male volunteers". Psychopharmacology. 106 (4): 511–6. doi:10.1007/BF02244823. PMID 1349754.
  24. 1 2 Serfaty M, Masterton G (1993). "Fatal poisonings attributed to benzodiazepines in Britain during the 1980s". Br J Psychiatry. 163 (3): 386–93. doi:10.1192/bjp.163.3.386. PMID 8104653.
  25. ↑ Olive G; Dreux C. (January 1977). "Pharmacologic bases of use of benzodiazepines in peréinatal medicine". Arch Fr Pediatr. 34 (1): 74–89. PMID 851373.
  26. ↑ Aso, Yukio; et al. (1988). "The Kinetics of the Racemization of Oxazepam in Aqueous Solution". Chemical and Pharmaceutical Bulletin. 36 (5): 1834–1840. doi:10.1248/cpb.36.1834. Retrieved September 9, 2016.
  27. ↑ Crossley, Roger J. (1995). Chirality and Biological Activity of Drugs. CRC Press. ISBN 0849391407.
  28. ↑ Griffiths RR, Johnson MW (2005). "Relative abuse liability of hypnotic drugs: a conceptual framework and algorithm for differentiating among compounds". J Clin Psychiatry. 66 Suppl 9: 31–41. PMID 16336040.
  29. ↑ Bergman U; Dahl-Puustinen ML. (1989). "Use of prescription forgeries in a drug abuse surveillance network". Eur J Clin Pharmacol. 36 (6): 621–3. doi:10.1007/BF00637747. PMID 2776820.
  30. ↑ Griffiths RR, Wolf B (August 1990). "Relative abuse liability of different benzodiazepines in drug abusers". J Clin Psychopharmacol. 10 (4): 237–43. doi:10.1097/00004714-199008000-00002. PMID 1981067.
  31. ↑ http://www.incb.org/pdf/e/list/green.pdf
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