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
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.
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.
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Last Updated: Feb 1, 2011