Midazolam Dosing for Agitation in Psychiatric Patients
For agitation in psychiatric patients, midazolam should be administered at 5 mg intramuscularly (IM) as the initial dose, with lower doses (2.5-5 mg) for intravenous (IV) or subcutaneous (SC) administration. 1
Initial Dosing Recommendations
- For IM administration: 5 mg is the standard initial dose 2, 3, 4
- For IV/SC administration: 2.5 mg initially (up to 5 mg maximum), given every 1 hour as needed 1
- For elderly, frail patients, or those with COPD: Use lower doses (0.5-1 mg IV/SC) 1
- For severe agitation requiring rapid control: Midazolam provides more effective sedation at 15 minutes compared to haloperidol and ziprasidone 3
Route of Administration Considerations
- Intramuscular (IM): Onset within 15 minutes, peaking at 30-60 minutes 5, 6
- Intravenous (IV): Onset within 1-2 minutes, peak effect in 3-4 minutes 1
- Intranasal (IN): Similar effectiveness to IM (75.4% vs 71.0%) with no significant difference 4
Special Patient Populations
- Patients over 60 years of age: Reduce dose by at least 50%; consider 0.5-1 mg IV/SC 1
- Patients with hepatic or renal impairment: Reduce dose due to decreased clearance 7, 5
- Patients receiving concomitant CNS depressants or opioids: Reduce midazolam dose by approximately 30% due to synergistic effects 1, 7
Monitoring and Safety
- Monitor respiratory status continuously, as respiratory depression is the major side effect 7, 8
- Have resuscitation equipment readily available regardless of administration route 7
- Observe for paradoxical reactions (increased agitation, anxiety, insomnia) which can occur with benzodiazepines 1
- Be aware of increased risk of falls, especially in elderly patients 1
Follow-up Dosing
- If additional doses are needed, administer after a thorough clinical evaluation 5, 6
- Consider a second dose of 5 mg IM if the first dose is insufficient 4
- For persistent agitation requiring scheduled dosing, use the lowest effective dose for the shortest period possible 1
Important Caveats
- Benzodiazepines are the treatment of choice for agitation related to alcohol or benzodiazepine withdrawal 1
- Midazolam can itself cause delirium or paradoxical agitation in some patients 1
- Fatalities have been reported with concurrent use of benzodiazepines with high-dose olanzapine 1
- Flumazenil may be used to reverse life-threatening respiratory depression, but will also reverse sedative effects 7