Maternal and neonatal elimination of amobarbital after treatment of the mother with barbiturates during late pregnancy.

Plasma half-lives of amobarbital were determined in newborn children of 10 mothers who had been treated with barbiturates for hypertension in pregnancy for 6 to 42 days prior to delivery. Five mothers had received amobarbital, 200 mg daily, and 5, phenobarbital, 60 to 180 mg daily. Half-lives in 7 of the babies ranged from 16.6 to 49.4 hr, comparable to those previously reported in babies of mothers who had received only a single dose of amobarbital. Thus there was no evidence of induction of amobarbital hydroxylation in these children. Two babies who had a greater than normal rise in serum bilirubin had longer half-lives (86.1 and 117.7 hr). In 1 baby whose mother had membranous glomerulonephritis, plasma amobarbital concentration did not significantly change over the period of the study.