Olanzapine
Antipsychotic — atypical
Indications
SchizophreniaAcute maniaBipolar maintenance
Adult dose
5–20 mg OD (usual 10 mg). IM acute: 5–10 mg, max 20 mg/24h.
Paediatric dose
Not first-line; specialist initiation only.
Common side effects
Marked weight gainSedationDyslipidaemiaHyperglycaemiaAnticholinergic
Serious side effects
Diabetes / DKANMSTardive dyskinesiaSevere metabolic syndromeVTE
Contraindications
Narrow-angle glaucoma (caution)
Monitoring
- Baseline & ongoing: weight, BMI, waist, BP, fasting glucose/HbA1c, lipids, prolactin, LFTs, ECG if risk
- Frequency: weekly weight first 6 weeks, then 12-weekly first year
Notable interactions
- Smoking induces CYP1A2 (lowers levels — review on cessation)
- Fluvoxamine raises levels
- CNS depressants
Curated reference based on BNF, Maudsley Prescribing Guidelines and NICE. Verify against current BNF and local guidelines before prescribing.