Recommended Midazolam Dosing for Acute 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. 1
Route-Specific Dosing for Seizures
First-line options:
- Intramuscular (IM): 0.2 mg/kg (maximum: 6 mg per dose); may repeat every 10-15 minutes 1
- Intranasal (IN): 0.2-0.3 mg/kg (Note: 0.1 mg/kg is subtherapeutic for intranasal administration) 2, 3
- Buccal: 0.3 mg/kg 4
For refractory status epilepticus:
- Intravenous (IV): Loading dose 0.15-0.20 mg/kg, followed by continuous infusion of 1 μg/kg/min, increasing by increments of 1 μg/kg/min (maximum: 5 μg/kg/min) every 15 minutes until seizures stop 1, 5
Comparative Efficacy by Route
The choice of administration route should be based on the clinical setting:
- IM, IN, and buccal routes show similar efficacy in terminating seizures (91-94% success rate) 6
- IN midazolam is equally effective as IV/rectal benzodiazepines in aborting seizures and may lead to faster cessation of seizures from time of hospital arrival 3
- Buccal midazolam at 0.3 mg/kg shows 100% efficacy for seizures lasting less than 30 minutes 4
- IV midazolam at doses of 2.5-15 mg has been shown to rapidly terminate seizures, including in status epilepticus 7
Important Clinical Considerations
Safety precautions:
- Be prepared to provide respiratory support regardless of administration route 1, 5
- Monitor oxygen saturation continuously 1, 5
- There is an increased incidence of apnea when midazolam is combined with other sedative agents, particularly opioids 1, 5
- Apnea may occur up to 30 minutes after the last dose 1, 5
Special populations:
- Reduce dose by 20% or more in patients over 60 years old or with ASA physical status III or higher 1, 5
- Dose adjustments are necessary for patients with hepatic or renal insufficiency 5
Reversal agent:
- Flumazenil may be administered to reverse life-threatening respiratory depression caused by midazolam 1
- Caution: Flumazenil will also reverse the anticonvulsant effects and may precipitate seizure recurrence 1, 5
Route Selection Algorithm
- If IV access is already established: Use IV route (0.15-0.20 mg/kg)
- If no IV access and rapid control needed:
- In prehospital/home setting: Use IN (0.2-0.3 mg/kg) or buccal (0.3 mg/kg) route
- In hospital setting with trained personnel: Use IM route (0.2 mg/kg)
- For prolonged seizures/status epilepticus: Establish IV access for continuous infusion
Recent evidence suggests that intranasal midazolam at 0.1 mg/kg may be subtherapeutic, with 25% of patients requiring redosing compared to 14% with other routes 2. Therefore, higher intranasal doses (0.2-0.3 mg/kg) should be considered for effective seizure control.