IV Midazolam Dosing for Pediatric Convulsive Seizures

Initial Bolus Dosing

The American Academy of Pediatrics recommends an initial IV bolus of 0.1 mg/kg (maximum 5 mg) administered slowly over 2–3 minutes for acute convulsive seizures or status epilepticus in children; the dose may be repeated every 10–15 minutes if seizures persist, with escalation to a higher loading dose for refractory cases. 1
A standard IV dose range of 0.05–0.10 mg/kg (maximum 5 mg) given over 2–3 minutes is supported for initial treatment. 1
Peak anticonvulsant effect occurs 3–5 minutes after injection; clinicians should wait this interval before redosing to avoid oversedation. 1
Re‑dosing may be performed every 10–15 minutes while seizures continue. 1

If seizures persist after repeated bolus doses, a loading dose of 0.15–0.20 mg/kg IV should be administered. 1
Following the loading dose, start a continuous infusion at 1 µg/kg/min (≈0.06 mg/kg/hr). 1
The infusion can be titrated upward by 1 µg/kg/min every 15 minutes until seizure control is achieved. 1
The maximum infusion rate is 5 µg/kg/min (≈0.3 mg/kg/hr), maintained until seizures stop. 1

For neonates and infants younger than 1 month, use extreme caution: employ the lower end of the pediatric range (≈0.05 mg/kg) and extend the administration time beyond 2–3 minutes to reduce the risk of apnea and cardiovascular instability. 1

The risk of respiratory depression is highest when midazolam is combined with other sedatives or opioids; clinicians should be vigilant. 1
Continuous pulse‑oximetry is required, and personnel must be ready to provide respiratory support irrespective of the administration route. 1
Flumazenil should be immediately available to reverse life‑threatening respiratory depression, recognizing that it also reverses the anticonvulsant effect and may precipitate seizures. 1

Wait the full 3–5 minutes for peak effect before giving an additional dose to prevent cumulative oversedation. 1
Administer the IV bolus slowly over 2–3 minutes to avoid hypotension and oversedation. 1
Paradoxical agitation occurs in roughly 6 % of younger children; consider alternative agents if this reaction develops. 1

The American Academy of Pediatrics recommends administering intranasal midazolam 0.2 mg/kg (maximum 6 mg per dose) as the preferred first-line treatment when intravenous access is unavailable, or intravenous midazolam 0.1 mg/kg if IV access is established 2
For the intravenous route, the initial dose is 0.05-0.10 mg/kg administered slowly over 2-3 minutes (maximum single dose: 5 mg), with peak effect occurring at 3-5 minutes after administration, and may be repeated every 10-15 minutes if seizures persist 2, 3
The intramuscular route is an alternative, with a dose of 0.2 mg/kg (maximum 6 mg per dose), which may be repeated every 10-15 minutes if needed 2

For refractory seizures, a loading dose of 0.15-0.20 mg/kg IV is recommended, followed by a continuous infusion starting at 1 μg/kg/min (0.06 mg/kg/hr), which can be titrated by increments of 1 μg/kg/min every 15 minutes up to a maximum of 5 μg/kg/min (0.3 mg/kg/hr) until seizures stop 2, 3

There is an increased risk of apnea, especially when combined with other sedatives, and oxygen saturation should be monitored continuously, with preparation to provide respiratory support regardless of administration route 2, 3
Flumazenil should be available to reverse life-threatening respiratory depression, though this will also reverse anticonvulsant effects 2, 3

Lower doses of midazolam are ineffective for seizure control, and rapid IV administration should be avoided to prevent oversedation and hypotension 2, 3
Paradoxical agitation, especially in younger children, should be watched for, and treatment should not be delayed attempting IV access when the intranasal route is immediately available 2

The American College of Emergency Physicians recommends reducing all doses by 30-50% when combined with opioids or other CNS depressants 4
The American Academy of Pediatrics suggests that patients with hepatic impairment require dose reduction due to decreased clearance, although the exact reduction percentage is not specified 4

The American Heart Association advises that respiratory depression risk is highest when midazolam is combined with fentanyl or other opioids 4