Olanzapine (Zyprexa) Treatment and Dosage Guidelines
For adult patients with schizophrenia or bipolar disorder, olanzapine (Zyprexa) should be administered at an initial dose of 5-10 mg once daily, with a target dose of 10 mg/day, and should not exceed 20 mg/day in most clinical situations. 1
Dosing Guidelines by Condition
Schizophrenia
Adults:
- Starting dose: 5-10 mg once daily
- Target dose: 10 mg/day
- Maximum dose: 20 mg/day
- Dosage adjustments should occur at intervals of not less than 1 week 1
Adolescents:
- Starting dose: 2.5-5 mg once daily
- Target dose: 10 mg/day (mean modal dose in clinical trials: 12.5 mg/day)
- Maximum dose: 20 mg/day
- Dosage adjustments: 2.5-5 mg increments/decrements 1
Bipolar I Disorder (Manic or Mixed Episodes)
Adults:
- Starting dose: 10-15 mg once daily
- Effective dose range: 5-20 mg/day
- Dosage adjustments should occur at intervals of not less than 24 hours
- Adjunctive to lithium or valproate: Start with 10 mg once daily 1
Adolescents:
- Starting dose: 2.5-5 mg once daily
- Target dose: 10 mg/day
- Maximum dose: 20 mg/day
- Dosage adjustments: 2.5-5 mg increments/decrements 1
Agitation Associated with Schizophrenia and Bipolar I Mania
- Intramuscular injection:
- Recommended dose: 10 mg
- Lower doses (5-7.5 mg) may be considered when clinically warranted
- If agitation persists, subsequent doses up to 10 mg may be given 1
Special Populations
Elderly or Debilitated Patients
- Starting dose: 2.5-5 mg once daily
- Dose escalation should be performed with caution 1
- For geriatric patients with dementia-related agitation: 2.5 mg/day, maximum 10 mg/day 2
Hepatic Impairment
- Starting dose: 5 mg once daily
- Dose escalation should be performed with caution 1
Administration
- Administer once daily without regard to meals
- For orally disintegrating tablets (ZYPREXA ZYDIS):
- Remove tablet with dry hands
- Place entire tablet in mouth
- Tablet disintegrates rapidly in saliva and can be swallowed with or without liquid 1
Efficacy and Monitoring
- Efficacy in schizophrenia was demonstrated in a dose range of 10-15 mg/day in clinical trials 1
- Short-term antimanic efficacy was demonstrated in a dose range of 5-20 mg/day 1
- Patients should be periodically reassessed to determine the need for maintenance treatment 1
- Monitor for adverse effects, particularly:
- Weight gain
- Sedation/somnolence
- Orthostatic hypotension
- Metabolic effects (long-term use) 3
Important Considerations
Adverse Effects
- Most common adverse reactions: somnolence, agitation, insomnia, headache 4
- Dose-dependent adverse reactions: constipation, dry mouth 4
- Weight gain is more common with olanzapine than with haloperidol or risperidone 5
- Unlike clozapine, olanzapine does not cause agranulocytosis 4
Cautions
- Avoid combining with benzodiazepines due to risk of oversedation and respiratory depression 3
- Monitor for extrapyramidal symptoms, though these are less common with olanzapine than with typical antipsychotics 5
- For treatment-resistant cases, some evidence suggests higher doses (>20 mg/day) may be beneficial in selected patients, but this must be balanced against increased risk of adverse effects 6, 7
Maintenance Treatment
- For schizophrenia: Effectiveness of 10-20 mg/day in maintaining treatment response has been demonstrated 1
- For bipolar I disorder: Maintenance monotherapy at 5-20 mg/day has shown benefit 1
- Healthcare providers should periodically reevaluate the long-term usefulness of the drug for individual patients 1
Olanzapine offers effective treatment for schizophrenia and bipolar disorder with a favorable adverse effect profile compared to typical antipsychotics, though weight gain remains a significant concern that requires monitoring.