RxPG - the perfect Rx for medical Post Graduate entrance blues!
Mobile Edition | Help/Newbie? | 24/7 Support
HOT | PrePG | MCQ | DNB | Careers | Books | Colleges | Dental | DocIndia | PLAB |  USMLE  | Australia | Canada | GLOBAL | OffBeat!
Articles | Forums | MCQ Crammer | Downloads | Mnemonics | Revision Tools | Recent Shouts | All Features


Olanzapine - Thienobenzodiazepine Atypical Antipsychotic

Author: wikipedia, Posted on Tuesday, November 01 @ 06:02:09 IST by RxPG  

 FRIEND Add to My Pages   PRINTER Printer Friendly   FRIEND Email Story  FRIEND Download Story  Psychiatry alerts 

Psychiatry

Olanzapine was the second atypical antipsychotic to gain FDA approval and has become one of the most commonly used atypical antipsychotics. Olanzapine has been FDA approved for the treatment of schizophrenia, acute mania in bipolar disorder, agitation associated with schizophrenia and bipolar disorder, and as maintenance treatment in bipolar disorder. Olanzapine can also be used to treat anxiety, although it is not commonly recommended for that purpose due to the strong side effects and expense. In particular, unlike benzodiazapenes, antipsychotics are non-addictive. Some psychiatrists have also been known to prescribe it to eating disorder patients, due both to its mood stabilising effects and tendency to increase weight.

Pharmacology

Olanzapine is structurally similar to clozapine, and is classified as a thienobenzodiazepine. Olanzapine has a high affinity for dopamine and serotonin receptors. Like most atypical antipsychotics compared to the older typical ones, Olanzapine has a lower affinity for histamine, cholinergic muscarinic and alpha adrenergic receptors. The mechanism of action of olanzapine is unknown, however it is theorized that olanzapine's antipsychotic activity is mediated primarily by antagonism at dopamine receptors, specifically D2. Serotonin antagonism may also play a role in the effectiveness of olanzapine, but the significance of 5-HT2A antagonism is debated among researchers. Antagonism at muscarinic, histaminic and alpha adrenergic receptors likely explains some of the side effects of olanzapine, such as anticholinergic effects, weight gain, sedation and orthostatic hypotension.

Pharmacokinetics

Olanzapine displays linear kinetics. Its elimination half-life ranges from 21 to 54 hours. Steady state plasma concentrations are achieved in about a week. Olanzapine undergoes extensive first pass metabolism and bioavailability is not affected by food.

Metabolism

Olanzapine is metabolized by the Cytochrome P450 system isoenzymes 1A2 and 2D6 (minor pathway). Drug metabolism may be increased or decreased by agents that induce (e.g. cigarette smoke) or inhibit (e.g. fluvoxamine or ciprofloxacin) CYP1A2 activity respectively.

Adverse events

Adverse events reported in the package insert for olanzapine include dry mouth, dizziness, sedation, insomnia, orthostasic hypotension, akathisia, and weight gain. Olanzapine is reported to cause extrapyramidal symptoms, tardive dyskinesia and neuroleptic malignant syndrome, although at a much reduced rate when compared to the classical antipsychotics.

Recently the FDA required the manufacturers of all atypical antipsychotics to include a warning about the risk of hyperglycemia and diabetes with atypical antipsychotics. Additionally there are some case reports of olanzapine-induced diabetic ketoacidosis. There is data showing that olanzapine can decrease insulin sensitivity. In addition, increased triglyceride levels may also be an issue with olanzapine. Impaired glucose metabolism, high triglycerides, and obesity have been shown to be constituents of the metabolic syndrome and may increase the risk of cardiovascular disease. The data suggests that olanzapine may be more likely to cause adverse metabolic effects than some of the other atypical antipsychotics.

Citing an increased risk of stroke, in 2004 the Committee for the Safety of Medicines (CSM) in the UK issued a warning that olanzapine and risperidone, both atypical antipsychotic medications, should not be given to elderly patients with dementia.

The results of a large, random-design study funded by NIH's National Institute of Mental Health (NIMH) were published in September 2005. The 18-month study, which involved 1,400 participants at 57 sites around the country, found that "patients on olanzapine also experienced substantially more weight gain and metabolic changes associated with an increased risk of diabetes than those participants taking the other drugs."


Note: This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article Olanzapine.



4 (Excellent) 3(Good) 2(Good) 1(Bad)   


Recommended Books for Psychiatry
 Books to read for Psychiatry by RxPG

Related Psychiatry articles
 Syndromes in Psychiatry
 Psychiatric Defence mechanisms - An Overview
 ICD diagnostic criteria in sexual disorders
 Schizophrenia - Overview of this common psychiatric disorder
 Organic mental disorders
 Confusing Features of Hallucinations
 Neurotic and Stress-Related Disorders
 Mental Disorders - An Introduction
 Features of Obsessive Compulsive Neurosis
 Which is the schizophrenia with worst prognosis?
 Suicide - Commonest cause of death among Psychiatric Patients
 Psychiatry Clinical Examination Format with Examples
 Psychotherapy: An Overview
 Mood Disorders (Affective Disorder)
 Defense Mechanisms in Psychodynamic Theory
 Mental Retardation (SYN. Learning Disabilities, Intellectual Impairment)
 Donepezil - centrally acting reversible acetyl cholinesterase inhibitor
 Olanzapine - Thienobenzodiazepine Atypical Antipsychotic
 Risperidone - Most Commonly Used Atypical Antipsychotic
 Clozapine - The First Atypical Antipsychotic

Related Psychiatry Discussions

Other articles by wikipedia
 What is a Personal Digital Assistant (PDA) - Overview
 Randomised Controlled Trials (RCT) - Introduction, Classification and Overview
 Overview of Types and Various Phases of Clinical Trials
 What is a Meta Analysis?
 What is a Systematic Review?
 What is a Clinical Audit?
 Oseltamivir (Tamiflu) - First Oral Influenza Neuraminidase Inhibitor
 Clopidogrel - The Super Aspirin
 Donepezil - centrally acting reversible acetyl cholinesterase inhibitor
 Topiramate - A Monosaccharide Anticonvulsant
 Digoxin - Cardiac Glycoside from Foxglove Plant
 Vigabatrin = VIsual side effects + GABA TRansaminase INhibitor
 Olanzapine - Thienobenzodiazepine Atypical Antipsychotic
 Risperidone - Most Commonly Used Atypical Antipsychotic
 Clozapine - The First Atypical Antipsychotic
 Quetiapine - D1 and D2 dopamine antagonist
 Ziprasidone - The Atypical Amongst Atypical Antipsychotics
 Alemtuzumab - Monoclonal Antibody Used in the Treatment of Leukemia and Lymphoma
 Abciximab - A Platelet Aggregation Inhibitor
 Bevacizumab (Avastin) - An Anti-Angiogenesis Anti Cancer Drug

 Psychiatry FAQ
  Browse all FAQs


Write an Article on Psychiatry
You can share your exam experiences, preparation strategies, books you have read or just any information about Psychiatry on RxPG website and we will publish it under your name.

Article Rating
Average Score: 4.2
Votes: 5




Most Read Article
Psychiatry; Free Online Mock Test 26

Related Links
· RxPG Postal Course
· Psychiatry Books at Amazon.com
· RxPG AIIMS Books
· Discuss Past Papers
· mediMOCK Forum
· RxPG Forums
· MRCPsych Forum
· NIMHANS Forum






ARTICLE TOOLS

· Psychiatry section
· Articles by wikipedia
· Add to my pages
· Printer friendly version
· PDF version
· Email article
· Feedback on this article
· Medical tutorials
· Related forum posts
· Related articles
· Related downloads
· Submit article
· Psychiatry alerts
· Psychiatry books
· Psychiatry past papers


Most read story about Psychiatry:
Psychiatry; Free Online Mock Test 26



Server Status: 293 pages served in last minute. Page generation time: 0.039 seconds
Site Maps: [Books] [News] [Forums] [Reviews] [Mnemonics]

sitemap - top30 - centuries - testimonials


About Us :: Disclaimer :: Contact Us :: Reporting abuse :: Terms of Services :: Privacy Policy

Advertise with RxPG!
Made in India by RxPG Medical Solutions Private Limited

"RxPG" is a Registered Trademark

Chrome Web Store YouTube Twitter LinkedIn Wikipedia Facebook