Phencyclidine: its transfer across the placenta as well as into breast milk.

Phencyclidine (PCP) is a dangerous and unpredictable drug which is widely abused among young people. Acute placental transfer of this drug was studied in pregnant rabbits and mice where it was shown to cross the placenta readily. Rabbit fetal levels of radioactivity reached their peak 2 hours after parenteral administration of PCP to the doe. In the mouse, where actual PCP levels were determined, there was a tenfold higher concentration of PCP in fetal tissue than in maternal blood. In lactating mice, the drug was found to cross rapidly into breast milk where it reached concentrations which were 10 times that of plasma. As PCP may be teratogenic and has been shown to be harmful to the infant during the postnatal period, those treating pregnant women should be aware to these possible routes of exposure for the developing infant and should counsel their patients accordingly.