Olanzapine Dosing
For most patients starting olanzapine, begin with 5-10 mg orally once daily, with a target dose of 10 mg/day within several days. 1
Standard Oral Dosing for Schizophrenia
- Initial dose: 5-10 mg once daily without regard to meals 1
- Target dose: 10 mg/day should be reached within several days 1
- Dose range: 10-15 mg/day was demonstrated effective in clinical trials, though doses above 10 mg/day showed no additional efficacy benefit 1
- Maximum dose: 20 mg/day - olanzapine is not indicated for doses above this level 1
- Dose adjustments: If needed, make changes in 5 mg increments at intervals of at least 1 week (time to steady state) 1
Bipolar I Disorder (Manic or Mixed Episodes)
- Initial dose: 10-15 mg once daily for acute mania 1
- Dose range: 5-20 mg/day demonstrated antimanic efficacy in 3-4 week trials 1
- Dose adjustments: Make changes in 5 mg increments at intervals of at least 24 hours 1
Special Populations Requiring Lower Starting Doses
Start with 5 mg once daily in patients who are: 1
- Debilitated
- Predisposed to hypotensive reactions
- Elderly (≥65 years, particularly nonsmoking females)
- More pharmacodynamically sensitive to olanzapine
Start with 2.5 mg in patients with: 2
- Hepatic impairment
- Alzheimer's disease-related agitation
Adolescent Dosing (Schizophrenia)
- Initial dose: 2.5-5 mg once daily 1
- Target dose: 10 mg/day 1
- Dose range: 2.5-20 mg/day (mean modal dose 12.5 mg/day in trials) 1
- Dose adjustments: Make changes in 2.5-5 mg increments 1
- Pharmacokinetic data suggest adolescents metabolize olanzapine similarly to nonsmoking adults, making standard adult dosing appropriate for most adolescents 3
Intramuscular Dosing for Acute Agitation
- Recommended dose: 10 mg IM for agitation associated with schizophrenia or bipolar mania 1
- Alternative doses: 5 mg or 7.5 mg IM may be considered when clinical factors warrant 1
- Lower dose populations: 5 mg IM for geriatric patients; 2.5 mg IM for debilitated or hypotension-prone patients 1
- Repeat dosing: Additional doses up to 10 mg may be given, but wait at least 2 hours after initial dose and 4 hours after second dose 1
- Maximum daily dose: 30 mg IM total - higher doses or more frequent administration not evaluated 1
- Clinical trials demonstrated efficacy with IM doses ranging from 2.5-10 mg 4, 2
Important Clinical Considerations
Transition to oral therapy: Once clinically appropriate, switch from IM to oral olanzapine 5-20 mg/day 1
Common pitfalls to avoid:
- Do not combine IM olanzapine with benzodiazepines in the same syringe - this causes precipitation or delayed reconstitution 1
- Use extreme caution when combining olanzapine with benzodiazepines due to risk of oversedation, respiratory depression, and reported fatalities 2
- Assess for orthostatic hypotension before administering subsequent IM doses, especially after maximal dosing (3 doses of 10 mg) 1
Monitoring requirements:
- Monitor for drowsiness and sedation 2
- Monitor for orthostatic hypotension, particularly with IM administration 2, 1
- Monitor metabolic effects (weight gain, glucose, lipids) with long-term use 2
Doses Above 20 mg/day
While the FDA-approved maximum is 20 mg/day, some treatment-resistant patients in clinical practice receive higher doses (up to 40-60 mg/day) 5, 6. However, this exceeds FDA labeling and should only be considered in highly selected treatment-resistant cases, as a large trial showed increased risk of weight gain and elevated prolactin at 40 mg/day compared to 20 mg/day 5.