Clinical comparison of oral nifedipine and subcutaneous terbutaline for initial tocolysis

In search of further "first line" alternatives for reducing premature uterine irritability and contractions, oral nifedipine, a type II dihydropyridine calcium channel blocking agent, was selected for a prospective randomized comparison trial with an established subcutaneous terbutaline protocol. Patients without primary exclusion criteria for tocolysis, with gestational ages between 20 and 35 weeks, were eligible for the study. In this report, data from 52 patients have been collated and have undergone appropriate tests of significance (28 patients receiving nifedipine and 24 patients receiving terbutaline). Both agents were found to be highly effective for tocolysis, with a success rate of 68% for nifedipine and 71% for terbutaline. Although not statistically significant, a tendency toward a decrease in side effects was noted with nifedipine when compared with terbutaline. No deleterious maternal or fetal side effects were reported. Based on these data, nifedipine, given as a one time, 30 mg oral dose, proved to be as effective as the subcutaneous terbutaline injection protocol.