Recommended Intramuscular Olanzapine Dosing for Acute Agitation
The recommended intramuscular (IM) dose of olanzapine for acute agitation is 10 mg, with lower doses of 5-7.5 mg considered when clinical factors warrant. 1
Dosing Algorithm
Standard Dosing
- First-line dose: 10 mg IM
- This dose has demonstrated efficacy in controlling agitation in patients with schizophrenia and bipolar mania 1
- If agitation persists, subsequent doses up to 10 mg may be given, but:
- Wait at least 2 hours after initial dose
- Wait at least 4 hours after second dose
- Do not exceed 30 mg total daily dose 1
Special Populations Requiring Dose Adjustment
- Elderly or debilitated patients: 5 mg/injection 1
- Patients predisposed to hypotension: 2.5 mg/injection 1
- Patients with hepatic/renal impairment: 2.5 mg/injection 1
Administration Technique
- Inject slowly, deep into muscle mass
- Reconstitute with 2.1 mL Sterile Water for Injection to provide 5 mg/mL solution
- Use immediately (within 1 hour) after reconstitution 1
Injection Volumes by Dose
- 10 mg: Withdraw total contents of vial
- 7.5 mg: 1.5 mL
- 5 mg: 1 mL
- 2.5 mg: 0.5 mL 1
Efficacy Evidence
Multiple high-quality studies support olanzapine's efficacy for acute agitation:
- Olanzapine IM (10 mg) demonstrated significant reduction in agitation within 30 minutes of administration 2
- Olanzapine showed a clear dose-response relationship with 5 mg, 7.5 mg, and 10 mg doses all superior to placebo in reducing agitation 2
- In comparative studies, olanzapine was more effective than haloperidol 5 mg in achieving adequate sedation at 15 minutes 3
Safety Considerations
Orthostatic Hypotension
- Assess for orthostatic hypotension before administering subsequent doses
- Do not administer additional doses if clinically significant postural changes in systolic blood pressure occur 1
Drug Interactions
- Do not combine with benzodiazepines: Risk of respiratory depression when combined with high-dose olanzapine 4
- Physical incompatibility: Do not combine olanzapine with diazepam in same syringe (precipitation occurs) 1
Adverse Effects
- Olanzapine has a favorable safety profile compared to typical antipsychotics with lower incidence of extrapyramidal symptoms 2
- Sedation is common but distinct from non-specific sedative effects 5
- Monitor for hypotension, which is the most frequently reported adverse event 2
Transition to Oral Therapy
- When transitioning to oral therapy, olanzapine 5-20 mg/day can effectively maintain the reduction in agitation achieved with IM administration 6
- This transition approach has demonstrated superior extrapyramidal symptom profile compared to haloperidol 6
Comparative Efficacy
- In some studies, midazolam-based regimens achieved more rapid sedation than olanzapine alone 7
- However, olanzapine demonstrated better efficacy than haloperidol 5 mg and 10 mg for achieving adequate sedation at 15 minutes 3
Clinical Pitfalls to Avoid
- Do not exceed maximum dosing recommendations (30 mg/day total, no more than 3 doses in 24 hours) 1
- Avoid simultaneous use with other CNS depressants due to risk of adverse events 5
- Do not administer intravenously or subcutaneously; IM route only 1
- Always inspect solution for particulate matter and discoloration before administration 1
By following these evidence-based dosing recommendations and safety precautions, olanzapine IM can be effectively used to manage acute agitation while minimizing adverse effects.