Effects of nifedipine on oxytocin- and prostaglandin F2 alpha -induced activity in the postpartum uterus.

In order to get additional information on spontaneous and drug-induced uterine activity in the early postpartum period, intrauterine pressure was registered by the microtransducer technique in 19 patients. The effects of the calcium entry blocker nifedipine were also tested. Myometrial activity was induced by infusion of oxytocin (10 patients) or prostaglandin F 2 alpha (nine patients). Both hormones increased myometrial activity, with slightly different patterns of contractility. Nifedipine effectively reduced contractions induced by both drugs. The microtransducer technique seems to be a convenient and safe method for studying the effects of drugs and hormones on uterine activity post partum. Furthermore, nifedipine administered orally is a potent inhibitor of drug-induced myometrial activity in the early postpartum period.