What is the recommended dose and administration of intranasal (IN) midazolam for acute seizure management?

Intranasal Midazolam for Acute Seizure Management

For acute seizure management, administer intranasal midazolam at 0.2 mg/kg (maximum 10 mg), divided equally between both nostrils, and repeat once after 5-10 minutes if seizures persist before escalating to alternative therapies. 1, 2, 3

Dosing Algorithm

Standard Dosing

• Administer 0.2 mg/kg intranasally, divided equally between both nostrils 2, 3
• Weight-based maximum: 5 mg for patients <50 kg; 10 mg for patients ≥50 kg 4
• This dose is higher than the 0.1 mg/kg dose, which has been shown to be subtherapeutic with a 25% redosing rate 5

Repeat Dosing Protocol

• If seizures continue, repeat the same dose after 5-10 minutes 1
• Maximum of 2-3 doses total before escalating to alternative therapies or seeking emergency care 1
• After the second dose without seizure cessation, immediately transition to emergency medical services 1

Critical Timing Consideration

• Immediately follow with a long-acting anticonvulsant (phenytoin/fosphenytoin or oral carbamazepine) because benzodiazepines redistribute rapidly and seizures often recur within 15-20 minutes 1

Administration Technique

Proper Delivery Method

• Position patient on their side to prevent aspiration 1
• Divide dose equally between both nostrils for optimal absorption 3
• If excessive head movement occurs during seizures, consider buccal administration instead 4
• Poor technique accounts for the majority of treatment failures—ensure caregivers are properly trained 4

Efficacy Evidence

The evidence strongly supports intranasal midazolam's effectiveness:

• Seizure cessation rate of 93.3% in prehospital settings when using 0.2 mg/kg 6
• Faster seizure control than IV diazepam when accounting for IV line establishment time (3.16 minutes vs 6.42 minutes) 3
• Comparable efficacy to intramuscular and buccal routes with no statistically significant differences 6
• 79 of 84 treatment episodes (94%) were clinically effective in adolescents and adults with severe epilepsy 4

Safety Monitoring

Respiratory Surveillance

• Monitor oxygen saturation and respiratory status continuously, especially with repeat dosing 1
• Respiratory depression occurs in approximately 1% of cases, significantly lower than local mucosal irritation (occurs in <33% of cases) 2
• Monitor for up to 30 minutes after administration as respiratory depression can be delayed 7

High-Risk Populations Requiring Dose Reduction

• Patients with hepatic impairment: Reduce dose by at least 20% due to decreased clearance 1
• Concurrent CNS depressants or opioids: Reduce dose by at least 20% due to synergistic respiratory depression risk 7, 1
• Underlying respiratory disease: Exercise heightened caution and consider dose reduction 1

Common Pitfalls to Avoid

Dosing Errors

• Do not use 0.1 mg/kg for intranasal administration—this dose is subtherapeutic and associated with a 25% redosing rate compared to 14% with other routes 5
• Do not exceed 2-3 total doses before escalating care, as this delays definitive treatment 1

Administration Errors

• Ensure proper technique training for caregivers, as poor delivery technique is the most common cause of treatment failure 4
• Do not delay long-acting anticonvulsant administration—benzodiazepines alone have short duration of action 1

Clinical Decision Errors

• Do not combine with other CNS depressants without dose adjustment, as this dramatically increases respiratory depression risk 7, 1
• Do not use in patients unable to protect their airway without appropriate monitoring and resuscitation equipment available 1