Olanzapine Dosing Recommendations
For adults with schizophrenia, start olanzapine at 5-10 mg once daily with a target dose of 10 mg/day, as doses above 10 mg/day have not demonstrated superior efficacy despite being FDA-approved up to 20 mg/day. 1
Schizophrenia Dosing
Adults
- Initial dose: 5-10 mg once daily, taken without regard to meals 1
- Target dose: 10 mg/day, achievable within several days 1
- Dose adjustments: Make changes in 5 mg increments at intervals of at least 1 week (the time needed to reach steady state) 1
- Efficacy range: 10-15 mg/day demonstrated in clinical trials, though doses above 10 mg/day showed no additional benefit over 10 mg/day 1
- Maximum dose: 20 mg/day (olanzapine is not indicated above this dose) 1
Special Populations Requiring Lower Starting Dose (5 mg)
The FDA mandates a 5 mg starting dose for patients who are: 1
- Debilitated
- Predisposed to hypotensive reactions
- Nonsmoking females ≥65 years of age
- More pharmacodynamically sensitive to olanzapine
Dose escalation in these patients must be performed with caution. 1
Adolescents with Schizophrenia
- Initial dose: 2.5-5 mg once daily 1
- Target dose: 10 mg/day 1
- Dose adjustments: 2.5-5 mg increments 1
- Mean effective dose in trials: 11.1 mg/day (mean modal dose 12.5 mg/day) 1
- Maximum evaluated dose: 20 mg/day (safety above this not established) 1
Bipolar I Disorder (Manic or Mixed Episodes)
Adults
- Initial dose: 10-15 mg once daily 1
- Dose adjustments: 5 mg increments at intervals of at least 24 hours 1
- Efficacy range: 5-20 mg/day demonstrated in 3-4 week trials 1
- Maximum evaluated dose: 20 mg/day 1
Adolescents
- Initial dose: 2.5-5 mg once daily 1
- Target dose: 10 mg/day 1
- Dose adjustments: 2.5-5 mg increments 1
- Maximum evaluated dose: 20 mg/day 1
Acute Agitation (Intramuscular Formulation)
Adults with Schizophrenia or Bipolar I Mania
- Recommended dose: 10 mg intramuscularly 1
- Lower dose options: 5 mg or 7.5 mg when clinically warranted 1
- Repeat dosing: Additional doses up to 10 mg may be given, but no more frequently than 2 hours after the first dose and 4 hours after the second dose 1
- Maximum daily dose: 30 mg total (three 10 mg injections) 1
Critical warning: Maximal IM dosing (three 10 mg doses given 2-4 hours apart) carries substantial risk of significant orthostatic hypotension—assess for orthostatic changes before each subsequent dose. 1
Special Populations (IM)
Dementia Patients (Off-Label Use)
According to the American Academy of Family Physicians: 2
- Initial dose: 2.5 mg/day
- Maximum dose: 10 mg/day
Treatment-Resistant Cases
While the FDA-approved maximum is 20 mg/day, research evidence suggests some treatment-resistant patients may respond to higher doses (40-60 mg/day) with good tolerability. 3 However, this exceeds FDA-approved dosing and should only be considered after failure of standard doses and other treatment options. 1
Key Clinical Considerations
Maintenance Treatment
- For schizophrenia, maintenance efficacy at 10-20 mg/day has been demonstrated in patients stable for approximately 8 weeks 1
- Periodically reassess the need for continued treatment and use the lowest effective dose 1
Common Pitfalls
- Most common adverse effects: Somnolence, weight gain (occurs in ~40% of patients, especially with high starting doses), agitation, insomnia, headache, constipation, and dry mouth 4, 5
- Weight gain is dose-dependent and more likely in underweight patients at baseline 5
- Unlike clozapine, olanzapine does not cause agranulocytosis and does not require baseline ECG monitoring 5
Dosing Misconceptions
- Smoking status does not necessitate dose adjustment despite CYP1A2 induction, as clinical studies show no association between smoking and need for higher doses 6
- Gender does not require dose adjustment in clinical practice 6
- Treatment resistance and longer hospital stays are associated with higher dose requirements, not demographic factors 6