Phenobarbital in the acute management of febrile convulsions.

Blood levels of phenobarbital were determined after a single oral or intramuscular (IM) dose in children in the hospital after febrile convulsions. At a dose of 15 mg/kg, both the oral and IM routes gave therapeutic blood levels within 90 minutes. Absorption from the IM route before 90 minutes was inconsistent and would be unlikely to arrest an established convulsion within a critical time period. For use as a drug to prevent convulsions, oral phenobarbital at 15 mg/kg deserves further study.