What is Olanzapine?

Olanzapine (trade names Zyprexa, Zyprexa Zydis, Zalasta, Zolafren, Olzapin, Rexapin or in combination with fluoxetine Symbyax) is an atypical antipsychotic, approved by the FDA for the treatment of schizophrenia and bipolar disorder.

The olanzapine formulations are manufactured and marketed by the pharmaceutical company Eli Lilly and Company, whose patent for olanzapine proper expires in 2011 (in October 2009 a Canadian judge ruled that the 1991 patent was invalid). Sales of Zyprexa in 2008 were $2.2B in the US alone, and $4.7B in total.

Olanzapine is available as a tablet in strengths of 2.5 mg, 5 mg, 7.5 mg, 10 mg, 15 mg and 20 mg. It also comes as an orally disintegrating wafer (known as Zydis), which dissolves on the tongue, in strengths of 5 mg, 10 mg, 15 mg and 20 mg. It is also available as a 10 mg vial for a rapid-acting intramuscular injection for short-term acute use.

Dose may be adjusted depending on the person' response to the drug. The dose also will depend on certain medical problems the person may have. It is generally recommended to be taken once daily before bed as it is highly sedating. However, sedation tends to diminish as treatment is pursued.

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


  • oral formulation: acute and maintenance treatment of Schizophrenia in adults, acute treatment of manic or mixed episodes associated with Bipolar I Disorder (monotherapy and in combination with lithium or valproate)
  • intramuscular formulation: acute agitation associated with Schizophrenia and Bipolar I Mania in adults
  • oral formulation combined with fluoxetine: acute treatment of depressive episodes associated with Bipolar I Disorder in adults, or acute treatment of treatment resistant depression in adults

Known FDA approvals are as follows:

  • approved for the ''treatment of the manifestations of psychotic disorders'' on September 6, 1996
  • approved in combination with fluoxetine for the ''treatment of depressive episodes associated with Bipolar disorder'' on December 24, 2003
  • approved for the ''long-term treatment of bipolar I disorder'' on January 14, 2004
  • approved in combination with fluoxetine for treatment resistant depression on March 19, 2009.

Off-label uses

Case-reports, open-label, and small pilot studies suggest efficacy of olanzapine for the treatment of some anxiety spectrum disorders (e.g. generalized anxiety disorder, panic disorder, post-traumatic stress disorder); however, olanzapine has not been rigorously evaluated in randomized, placebo-controlled trials for this use and is not FDA approved for these indications. Other common off-label uses of olanzapine include the treatment of eating disorders (e.g. anorexia nervosa) and as an adjunctive treatment for major depressive disorder without psychotic features. It has also been used for Tourette syndrome and stuttering. Olanzapine is also used in many addiction clinics as a sleep aid (usually 2.5–5 mg) due to its low abuse profile and zero addictive properties.

Prevention of psychosis

Olanzapine has been considered as part of an early psychosis approach for schizophrenia. The Prevention through Risk Identification, Management, and Education (PRIME) study, funded by the National Institute of Mental Health and Eli Lilly, tested the hypothesis that olanzapine might prevent the onset of psychosis in people at very high risk for schizophrenia. The study examined 60 patients with prodromal schizophrenia, who were at an estimated risk of 36–54% of developing schizophrenia within a year, and treated half with olanzapine and half with placebo. In this study, patients receiving olanzapine had a lower risk of progressing to psychosis, although the difference did not reach statistical significance. Olanzapine was effective for treating the prodromal symptoms, but was associated with significant weight gain.

Use in elderly

Citing an increased risk of stroke, in 2004 the Committee on 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. In the U.S., olanzapine comes with a black box warning for increased risk of death in elderly patients. It is not approved for use in patients with dementia-related psychosis. However, a BBC investigation in June 2008 found that this warning was being widely ignored by doctors.

Further Reading

This article is licensed under the Creative Commons Attribution-ShareAlike License. It uses material from the Wikipedia article on "Olanzapine" All material adapted used from Wikipedia is available under the terms of the Creative Commons Attribution-ShareAlike License. Wikipedia® itself is a registered trademark of the Wikimedia Foundation, Inc.

Last Updated: Sep 15, 2014

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