Olanzapine (sold under the trade name Zyprexa among others) is an atypical antipsychotic primarily used to treat schizophrenia and bipolar disorder. For schizophrenia, it can be used for both new-onset disease and long-term maintenance. It is taken by mouth or by injection into a muscle.Common side effects include weight gain, movement disorders, dizziness, feeling tired, constipation, and dry mouth. Other side effects include low blood pressure with standing, allergic reactions, neuroleptic malignant syndrome, high blood sugar, seizures, and tardive dyskinesia. In older people with dementia, its use increases the risk of death. Use in the later part of pregnancy may result in a movement disorder in the baby for some time after birth. Although how it works is not entirely clear, it blocks dopamine and serotonin receptors.Olanzapine was patented in 1991 and approved for medical use in the United States in 1996. It is available as a generic medication. In 2019, it was the 185th most commonly prescribed medication in the United States, with more than 3 million prescriptions. Lilly also markets olanzapine in a fixed-dose combination with fluoxetine as olanzapine/fluoxetine (Symbyax). Medical uses
Schizophrenia
The first-line psychiatric treatment for schizophrenia is antipsychotic medication, with olanzapine being one such medication. Olanzapine appears to be effective in reducing symptoms of schizophrenia, treating acute exacerbations, and treating early-onset schizophrenia. The usefulness of maintenance therapy, however, is difficult to determine, as more than half of people in trials quit before the 6-week completion date.
In 2021, Gottstein summarized this tangle of legal activities, and their impact on the political landscape of psychiatry and antipsychiatry in the US, in The Zyprexa Papers. Trade names
Olanzapine is generic and available under many trade names worldwide. Dosage forms
Olanzapine is marketed in a number of countries, with tablets ranging from 2.5 to 20 mg. Zyprexa (and generic olanzapine) is available as an orally disintegrating "wafer", which rapidly dissolves in saliva. It is also available in 10-mg vials for intramuscular injection. Research
Olanzapine has been studied as an antiemetic, particularly for the control of chemotherapy-induced nausea and vomiting (CINV).In general, olanzapine appears to be about as effective as aprepitant for the prevention of CINV, though some concerns remain for its use in this population. For example, concomitant use of metoclopramide or haloperidol increases the risk for extrapyramidal symptoms. Otherwise, olanzapine appears to be fairly well tolerated for this indication, with somnolence being the most common side effect.Olanzapine has been considered as part of an early psychosis approach for schizophrenia. The Prevention through Risk Identification, Management, and Education  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 did not have a significantly lower risk of progressing to psychosis.