Phenobarbital plasma levels in neonates.

This pilot study demonstrated marked variation in neonatal phenobarbital utilization. In order to rapidly achieve therapeutic levels, it is suggested that a loading dose of 8 to 10 mg per kg be administered for 2 days followed by reduction of dosage to a maintenance level of 5 to 6 mg per kg with frequent monitoring of plasma phenobarbital concentrations. The optimal plasma concentration of phenobarbital for control of neonatal seizures or withdrawal syndromes appeared to be between 15 to 30 mug per ml.