Pharmacokinetics of paraldehyde disposition in the neonate.

The pharmacokinetic parameters controlling paraldehyde elimination were determined in nine infants infused with paraldehyde at the rate of 150 mg/kg/hr in a 5% solution in 5% dextrose for the treatment of status epilepticus. The mean +/- SEM values for the observed parameters were as follows: rate constant for the disposition of paraldehyde 0.0680 +/- 0.0071 hr,-1 half-life 10.2 +/- 1.0 hr; volume of distribution 1.73 +/- 0.20 L/kg; clearance 0.121 +/- 0.023 L/hr/kg. Phenobarbital administration prior to or within 24 hours of the cessation of paraldehyde infusion decreased both paraldehyde clearance and volume of distribution in a manner linearly related to the logarithm of the phenobarbital dose. The rate constant for paraldehyde elimination was decreased as a linear function of the logarithm of the combined dose of administered phenobarbital and phenytoin. No acetaldehyde was detected in any blood samples. Paraldehyde administration was not correlated with any adverse reactions or toxicities.