Information last reviewed: May 2026 — for educational purposes only.
What Is Zyprexa (Olanzapine)?
Olanzapine, marketed as Zyprexa, is a second-generation (atypical) antipsychotic of the thienobenzodiazepine class. It exerts antagonism at dopamine D1–D4, serotonin 5-HT2A and 5-HT2C, muscarinic M1–M5, histamine H1, and adrenergic alpha-1 receptors. This broad receptor profile underlies comprehensive symptom control for both positive (hallucinations, delusions) and negative (flat affect, social withdrawal) symptoms of schizophrenia. Olanzapine is among the most effective antipsychotics clinically but carries a significant metabolic risk profile including weight gain, dyslipidaemia, and type 2 diabetes. An intramuscular (IM) formulation exists for acute agitation management.
Prescription (Rx) Status
Olanzapine is prescription-only (Schedule N). Generic tablets are widely available. The IM depot formulation (Zyprexa Relprevv) is managed under a restricted REMS programme due to post-injection delirium/sedation syndrome risk. FDA black-box: increased mortality in elderly patients with dementia-related psychosis; IM formulation black-box for sedation/delirium. Zyprexa + fluoxetine (Symbyax) is co-marketed for bipolar depression and treatment-resistant depression.
Uses of Olanzapine
FDA-approved for schizophrenia (adults and adolescents 13+), acute bipolar mania (monotherapy and adjunct), and bipolar maintenance. Combined with fluoxetine (Symbyax) for bipolar I depression and treatment-resistant depression. Injectable olanzapine treats acute agitation in schizophrenia and bipolar mania. Used off-label for anorexia nervosa, PTSD, and chemotherapy-induced nausea.
Tablet Strengths
Olanzapine oral tablets: 2.5 mg, 5 mg, 7.5 mg, 10 mg, 15 mg, and 20 mg. Orally disintegrating tablets (ZydisTM): same strengths. Schizophrenia starting dose: 5–10 mg/day. Target dose: 10–20 mg/day. Bipolar mania: 10–15 mg/day. Maximum: 20 mg/day. Morning vs. evening dosing depends on sedation tolerance. Lower starting doses used in elderly or hepatically impaired patients.
Price
Generic olanzapine tablets are affordable (~$20–$50/month). Zyprexa brand is significantly more expensive without insurance.
Frequently Asked Questions
Q: Does olanzapine always cause weight gain?
A: Weight gain is one of the most common and clinically significant side effects of olanzapine. Average weight gain of 4–10 kg over one year is reported. Metabolic monitoring every 3 months is recommended, including fasting glucose, lipids, and BMI. Switching to a metabolically neutral antipsychotic may be considered if weight gain is unmanageable.
Q: Can olanzapine treat anxiety or insomnia?
A: Olanzapine is occasionally used off-label for severe anxiety or insomnia at very low doses (1.25–2.5 mg), leveraging its sedating H1/M1 blockade. However, metabolic risks persist even at low doses, making it a last-resort option for those indications.
Q: How long does it take for olanzapine to work?
A: Sedation and calming effects appear within hours of the first dose. Antipsychotic efficacy (reduced hallucinations, delusions) typically builds over 2–4 weeks. Full therapeutic response for negative symptoms may take 3–6 months.
Disclaimer: This page is for informational purposes only and does not constitute medical advice. Olanzapine requires a valid prescription. Always consult a qualified healthcare professional. See our full disclaimer.