Ondansetron 1145676 215566840 2008-05-28T19:43:56Z ChemNerd 2246483 Quick-adding category "Imidazoles" (using [[WP:HOTCAT|HotCat]]) {{drugbox | | IUPAC_name = 9-methyl-3-[(2-methyl-1''H''-imidazol-1-yl)<br>methyl]-1,2,3,9-tetrahydrocarbazol-4-one | image = Ondansetron skeletal.svg | width = 200px | image2 = Ondansetron 3D.png | CAS_number = 99614-02-5 | ATC_prefix = A04 | ATC_suffix = AA01 | PubChem = 4595 | DrugBank = APRD00481 | C = 18 | H = 19 | N = 3 | O = 1 | molecular_weight = 325.9 g/mol | smiles = O=C1C(CCc2c1c1ccccc1n2C)Cn1ccnc1C | bioavailability = ~60% | protein_bound =70%-76% | metabolism = [[Liver|Hepatic]] ([[CYP3A4]], [[CYP1A2]], [[CYP2D6]]) | elimination_half-life = 5.7 hours | excretion = [[Kidney|Renal]] | pregnancy_AU = B1 | pregnancy_US = B | legal_AU = S4 | legal_UK = POM | legal_US = Rx-only | routes_of_administration = Oral, [[Suppository|rectal]], [[Intravenous therapy|IV]], [[Intramuscular injection|IM]] |}} '''Ondansetron''' ([[International Nonproprietary Name|INN]]) ({{pronEng|ɒnˈdænsɛtrɒn}}) or '''Zofran''' is a [[serotonin]] [[5-HT3 antagonist|5-HT<sub>3</sub> receptor antagonist]] used mainly as an [[antiemetic]] to treat [[nausea]] and [[vomiting]] following [[chemotherapy]]. Its effects are thought to be on both peripheral and central nerves. Ondansetron reduces the activity of the [[vagus nerve]], which activates the vomiting center in the [[medulla oblongata]], and also blocks serotonin receptors in the [[chemoreceptor trigger zone]]. It has little effect on vomiting caused by motion sickness, and does not have any effect on [[dopamine]] receptors or [[Muscarinic acetylcholine receptor|muscarinic receptor]]s. ==History== Ondansetron was developed around 1984 by scientists working at Glaxo's laboratories in [[London]]. After several attempts the company successfully filed for U.S. patent protection for the drug in 1986. [http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=4695578.PN.&OS=PN/4695578&RS=PN/4695578 U.S. Patent 4,695,578] was granted in September 1987 while [http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=4753789.PN.&OS=PN/4753789&RS=PN/4753789 U.S. Patent 4,753,789] was granted in June 1988. [http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5578628.PN.&OS=PN/5578628&RS=PN/5578628 U.S. Patent 5,578,628], a divisional patent of [http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=4753789.PN.&OS=PN/4753789&RS=PN/4753789 U.S. Patent 4,753,789], was granted in November 26, 1996. Ondansetron was granted [[Food and Drug Administration]] (FDA) approval as Zofran in January 1991. Glaxo did pediatric research on Zofran's uses, and gained patent extension as a result. Consequently U.S. exclusivity ended December 24, 2006. The FDA subsequently approved the first generic versions in December 2006, with marketing approval granted to Teva Pharmaceuticals USA and SICOR Pharmaceuticals. It is currently marketed by [[GlaxoSmithKline]] (GSK) under the trade name '''Zofran'''; other manufacturers include [[Cipla]] Ltd. ('''Emeset'''), [[Gedeon Richter Ltd.]] ('''Emetron'''), Korea United Pharmaceuticals ('''Emodan''') and Zentiva a.s. ('''Ondemet'''). On May 29, 2006, [[Baxter International|Baxter Healthcare]] received tentative approval<ref name="url">{{cite web |url=http://www.fda.gov/cder/foi/appletter/2006/021915s000TAltr.pdf |title=Center for Drug Evaluation & Research (FDA) letter of tentative approval for Ondansetron NDA by Baxter Healthcare Corp. |format= |work= |accessdate=}}</ref> to market its own label of Ondansetron Injection, USP, 8 mg/50 mL and 32 mg/50 mL iso-osmotic sodium chloride solution, after GSK's patent expired on December 24, 2006. ==Clinical uses== {{seealso|5-HT3 antagonist}} The 5-HT<sub>3</sub> receptor antagonists are the primary drugs used to treat and prevent [[chemotherapy]]-induced nausea and vomiting (CINV). Many times they are given intravenously about 30 minutes before beginning therapy. Ondansetron is also effective in controlling [[post-operative nausea and vomiting|post-operative]] (PONV) and post-radiation nausea and vomiting, and is a possible therapy for nausea and vomiting due to acute or chronic medical illness or acute [[gastroenteritis]]. Although it is highly effective, its high cost had limited its use to controlling PONV and CINV- although it is now available in cheaper generic forms. It is also used off-label to treat [[hyperemesis gravidarum]] in pregnant women, but there is no conclusive data available on its safety in [[pregnancy]], especially during the first [[trimester]]. It is also often used to treat [[cyclic vomiting syndrome]]; although there have been no formal trials to confirm efficacy, case reports suggest it can be helpful in some cases. The drug is administered 1–3 times daily, depending on the severity of nausea and/or vomiting. The normal oral dose for adults and children over the age of 12, is 8 mg initially, followed by a second dose of 8 mg, eight hours later. The drug is then administered once every 12 hours, usually not for more than 2-3 days. Following oral administration, it takes about 1.5–2 hours to reach maximum plasma concentrations. This drug is removed from the body by the [[liver]] and [[kidney]]s. The clinical effect of ondansetron (and other drugs from the same group) can be potentiated by combining it with [[dexamethasone]]. ===Investigational=== ====Schizophrenia==== A 2006 [[double-blind]], [[randomized controlled trial]] indicated that ondansetron may have value in the treatment of schizophrenia, as an adjunct to [[haloperidol]]. The study found the combination to [[statistical significance|significantly]] improve [[PANSS|negative]] schizophrenia symptoms, and people taking both drugs experienced fewer of the adverse effects commonly associated with haloperidol;<ref>{{cite journal |author=Zhang ZJ, Kang WH, Li Q, Wang XY, Yao SM, Ma AQ |title=Beneficial effects of ondansetron as an adjunct to haloperidol for chronic, treatment-resistant schizophrenia: a double-blind, randomized, placebo-controlled study |journal=[[Schizophrenia Research]] |volume=88 |issue=1-3 |pages=102–10 |year=2006 |pmid=16959472 |doi=10.1016/j.schres.2006.07.010}}</ref> an earlier, smaller, [[open-label trial]] had found ondansetron to be useful in treating [[antipsychotic]]-induced [[tardive dyskinesia]] in people with schizophrenia, and the study patients also showed significant improvement in the disease's symptoms.<ref>{{cite journal |author=Zullino DF, Eap CB, Voirol P |title=Ondansetron for tardive dyskinesia |journal=Am J Psychiatry |volume=158 |issue=4 |pages=657–8 |year=2001 |pmid=11282718 |doi=10.1176/appi.ajp.158.4.657-a}}</ref><ref>{{cite journal |author=Sirota P, Mosheva T, Shabtay H, Giladi N, Korczyn AD |title=Use of the selective serotonin 3 receptor antagonist ondansetron in the treatment of neuroleptic-induced tardive dyskinesia |journal=Am J Psychiatry |volume=157 |issue=2 |pages=287–9 |year=2000 |pmid=10671405 |doi=10.1176/appi.ajp.157.2.287}} [http://ajp.psychiatryonline.org/cgi/content/full/157/2/287 Free full text]</ref> ====Parkinson's disease==== Early studies have also examined ondansetron as a possible treatment for psychosis resulting from advanced [[Parkinson's disease]].<ref>{{cite journal |author=Zoldan J, Friedberg G, Livneh M, Melamed E |title=Psychosis in advanced Parkinson's disease: treatment with ondansetron, a 5-HT3 receptor antagonist |journal=Neurology |volume=45 |issue=7 |pages=1305–8 |year=1995 |pmid=7617188 |doi=}}</ref> Its ability to be of benefit despite lacking any significant antagonistic properties at [[dopamine receptors]] or the [[5-HT2A receptor]] raises interesting questions about the etiology of psychosis. ====Alcoholism==== Ondansetron lowers the cravings for alcohol, especially in early-onset alcoholics. In one cognitive-behavioral therapy study, ondansetron patients with early-onset alcoholism had fewer drinks per day and reported more days without drinking at all, compared to the other groups in the study. <ref>{{cite web| url=http://alcoholism.about.com/cs/meds/a/aa001120a.htm | title=Ondansetron can prevent alcohol craving| date=June 11, 2006| date accessed=Nov 5, 2007}}</ref><ref>{{cite journal |author=Sellers EM, Toneatto T, Romach MK, Somer GR, Sobell LC, Sobell MB |title=Clinical efficacy of the 5-HT3 antagonist ondansetron in alcohol abuse and dependence |journal=Alcohol Clin Exp Res |volume=18 |issue=4 |pages=879–85 |year=1994 |pmid=7978099 |doi=10.1111/j.1530-0277.1994.tb00054.x}}</ref> ==Adverse effects== Ondansetron is a well-tolerated drug with few side effects. Headache, constipation, and dizziness are the most commonly reported side effects associated with its use. There have been no significant drug interactions reported with this drug's use. It is broken down by the hepatic [[cytochrome P450]] system and it has little effect on the metabolism of other drugs broken down by this system. ==See also== * [[Granisetron]] * [[Dolasetron]] * [[Alosetron]] (not an antiemetic but another 5-HT<sub>3</sub> antagonist investigated for controlling [[irritable bowel syndrome]]) ==Notes== * Katzung, Bertram G. ''Basic and Clinical Pharmacology'', 9th ed. (2004). ISBN 0-07-141092-9 ==References== {{reflist}} {{5-HT3 antagonists}} [[Category:Antiemetics]] [[Category:5-HT3 antagonists]] [[Category:Imidazoles]] [[de:Ondansetron]] [[fr:Ondansétron]] [[hr:Ondansetron]] [[pl:Ondansetron]]