Chlorpromazine excretion by the neonate following chronic in utero exposure

The pharmacokinetics of chlorpromazine in the newborn have not been reported. We studied the kinetics of removal of chlorpromazine from plasma in an infant whose mother was treated with high doses of chlorpromazine and lithium throughout the last trimester of pregnancy. The infant exhibited symptoms of severe neurologic depression that slowly abated over the first 9 days of life. The kinetics of plasma chlorpromazine removal were described with a two-compartment model, exhibiting a rapid half-life of 1.46 days and a slow half-life of 3.19 days. Both half-lives are considerably longer than the rapid and slow half-lives described in adults. Caution in exposing the fetus or newborn to chlorpromazine is warranted. Further information on the distribution and excretion of chlorpromazine by the newborn is needed.