An antagonist at dopamine D1, D2, D4, serotonin 5-HT2A, 5-HT2C, 5-HT3, 5-HT6, muscarinic M1–M5, histamine H1, and α1-adrenoceptors. The broad receptor profile drives strong antipsychotic effect but also high metabolic disturbance and weight gain rates (among the highest in atypical antipsychotics). The Huhn 2019 network meta-analysis showed one of the highest efficacies. CYP1A2-metabolized.
Indications
A
Bipolar disorder maintenance
First line
First-line in acute mania and maintenance of bipolar I disorder per CANMAT 2018. Dose 10–20 mg daily. Combined with fluoxetine (Symbyax), -approved for bipolar depression and treatment-resistant depression.
First-line for schizophrenia and schizoaffective disorder per 2020 and NG178 (2020). Starting dose 5–10 mg once daily at bedtime, titrated to 10–20 mg. Among the most effective atypical antipsychotics (Huhn 2019), but choice is individualized due to metabolic adverse effects. In patients at metabolic syndrome risk, aripiprazole is preferred.
The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.
D
Chronic insomnia in adults under 55
Not recommended
Off-label low-dose olanzapine (2.5–5 mg at bedtime) for insomnia is common due to marked sedation via H1 blockade. 2017 does not recommend this use – evidence is absent, and the risk of metabolic disturbance, 5–10 kg weight gain over 6 months, type 2 diabetes, and tardive dyskinesia with prolonged use is not justified by the symptomatic effect. First-line for chronic insomnia is cognitive-behavioral therapy for insomnia (CBT-I). When pharmacotherapy is needed, melatonin or a sedating antidepressant are preferred.
Off-label use, common in Spain, Russia, and Latin America.
Before start and every 3 months, monitor weight, waist circumference, fasting glycemia, , lipid profile, and BP. Metabolic syndrome develops in 30–50% of patients on long-term therapy. With weight gain over 5 kg or glycemia rise, discuss switching to aripiprazole or ziprasidone with better metabolic profile. Not used in older adults with dementia.
Common myths
Myth: «low-dose olanzapine is the ideal sleep aid – mild sedation and no dependence.» Fact: even at 2.5 mg olanzapine raises appetite and metabolic risk; 5–10 kg weight gain over 6 months is typical. Tardive dyskinesia and neuroleptic malignant syndrome are rare but possible. Using olanzapine for insomnia without psychiatric disease is unjustified treatment with unpredictable risk-benefit balance. For insomnia, first-line is non-pharmacological (CBT-I, sleep hygiene).
Check interaction with another drug
Opens the checker prefilled with this drug. Pick the second one from your regimen.
FDA boxed warning: increased mortality in elderly patients with dementia on atypical antipsychotics. The Zyprexa Relprevv long-acting form carries post-injection delirium/sedation syndrome (PDSS) risk.
Contraindications
Olanzapine hypersensitivity
Angle-closure glaucoma
Dementia in older adults
Parkinson's disease, Lewy body dementia
Pregnancy (except life-saving indications)
Lactation
Age under 13
Serious adverse effects
Type 2 diabetes and diabetic ketoacidosis
Neuroleptic malignant syndrome
Tardive dyskinesia
Venous thromboembolism
QT prolongation
Cerebrovascular events in older adults with dementia
Common adverse effects
Weight gain (often 5–10 kg over 6 months)
Drowsiness and sedation
Hyperlipidemia, hyperglycemia
Dry mouth
Constipation
Orthostatic hypotension
PregnancyFDA C
T3 use carries neonatal extrapyramidal and withdrawal risk. In pregnant psychotic patients, decisions are made with the psychiatrist.
Breastfeeding
Milk concentrations are low. Use during lactation cautiously with monitoring of infant sedation and weight gain.
Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.
Frequently asked
What is Olanzapine used for?
Olanzapine is evaluated for the following indications with varying evidence strength: Schizophrenia (evidence tier A), Bipolar disorder maintenance (evidence tier A), Chronic insomnia in adults under 55 (evidence tier D). See the full indication matrix with dosing and citations above on this page.
What are the side effects of Olanzapine?
Common side effects of Olanzapine (≥ 1 in 100): Weight gain (often 5–10 kg over 6 months), Drowsiness and sedation, Hyperlipidemia, hyperglycemia, Dry mouth, Constipation, Orthostatic hypotension. See the Safety section for uncommon and serious reactions.
Is Olanzapine safe during pregnancy?
FDA category C. T3 use carries neonatal extrapyramidal and withdrawal risk. In pregnant psychotic patients, decisions are made with the psychiatrist.
Is Olanzapine compatible with breastfeeding?
Milk concentrations are low. Use during lactation cautiously with monitoring of infant sedation and weight gain.
Who should not take Olanzapine?
Olanzapine is contraindicated in: Olanzapine hypersensitivity; Angle-closure glaucoma; Dementia in older adults; Parkinson's disease, Lewy body dementia; Pregnancy (except life-saving indications). Full list in the Safety section.
Does Olanzapine carry an FDA boxed warning?
FDA boxed warning: increased mortality in elderly patients with dementia on atypical antipsychotics. The Zyprexa Relprevv long-acting form carries post-injection delirium/sedation syndrome (PDSS) risk.