Midazolam Dosing for Seizure Management
For acute seizure management, midazolam should be administered at 0.2 mg/kg intramuscularly (maximum: 6 mg per dose), which may be repeated every 10-15 minutes if needed, or intravenously at 0.15-0.20 mg/kg loading dose followed by continuous infusion starting at 1 μg/kg/min (maximum: 5 μg/kg/min). 1
Route-Specific Dosing Recommendations
Intramuscular (IM) Administration
- Initial dose: 0.2 mg/kg (maximum: 6 mg per dose)
- May repeat every 10-15 minutes if seizures persist 1
- For adults in status epilepticus, a fixed dose of 15 mg IM has shown efficacy 2
Intravenous (IV) Administration
- Loading dose: 0.15-0.20 mg/kg administered slowly over 2-3 minutes 1, 3
- Continuous infusion: Start at 1 μg/kg/min, increase by 1 μg/kg/min increments every 15 minutes until seizures stop (maximum: 5 μg/kg/min) 1
- For rapid seizure termination in adults, IV doses of 2.5-15 mg have been effective 4
Buccal Administration (alternative when IV/IM not available)
- 0.3 mg/kg placed in the buccal cavity
- Effective for seizures lasting less than 30 minutes with 84.2% success rate 5
Age-Specific Considerations
Pediatric Patients
- 6 months to 5 years: Initial dose 0.05-0.1 mg/kg (maximum total dose: 0.6 mg/kg, not to exceed 6 mg) 3, 6
- 6 to 12 years: Initial dose 0.025-0.05 mg/kg (maximum total dose: 0.4 mg/kg, not to exceed 10 mg) 3, 6
- 12 to 16 years: Dose as adults (maximum total dose usually does not exceed 10 mg) 3
Adult Patients
- Standard IV dose: 0.15-0.20 mg/kg loading dose 1
- For status epilepticus: 2.5-15 mg IV has been shown effective 4
Dose Adjustments
- Reduce dose by 20% or more in patients:
- Over 60 years old
- With ASA physical status III or higher
- With hepatic or renal insufficiency
- With chronic obstructive pulmonary disease 1
- When used with opioids, reduce midazolam dose due to synergistic effects 1
Monitoring Requirements
- Continuous oxygen saturation monitoring is essential
- Prepare respiratory support equipment before administration
- Monitor for respiratory depression, which is the primary adverse effect
- Be aware that apnea can occur up to 30 minutes after the last dose 1
- Monitor for hypotension, especially in critically ill patients 3
Precautions and Adverse Effects
- Respiratory depression is dose-dependent and more likely with:
- Flumazenil may be used to reverse life-threatening respiratory depression, but with caution as it may precipitate seizure recurrence 1
- Midazolam has a faster onset (1-2 minutes) and shorter duration (15-80 minutes) compared to diazepam 7
Clinical Pearls
- Midazolam is 1.5-3.5 times more potent than diazepam 1
- The use of H2 antagonists increases midazolam bioavailability by approximately 30% 1
- In prehospital settings, intranasal or intramuscular routes are preferred for initial administration 8
- Underdosing is common in emergency settings (72% of incorrect doses are lower than recommended) 8
- For optimal seizure control, accurate weight-based dosing is critical 8
Following these evidence-based recommendations will help ensure safe and effective seizure management with midazolam while minimizing the risk of adverse effects.