Efficacy, safety and tolerance of oral sustained-release ritodrine given after intravenous administration in the treatment of premature labor.

45 patients in premature labor entered the study, four dropped out for administrative reasons. The remaining 41 patients started all with an intravenous treatment followed by oral treatment with sustained-release ritodrine at a daily dosage of 120 mg per day until the 36th week of gestation. The mean gestational age at entry was 31.26 weeks +/- 3.27 and at delivery 37.76 weeks +/- 2.11 or a mean gain in days of 44.61 days +/- 20.85. A cluster analysis splitting the patients into four groups regarding the gestational age at entry and the Baumgarten tocolytic index showed that even the high-risk patients benefit remarkably by the treatment. The side effect rate was low as well for palpitation as for tremor. The patient compliance was excellent. No neonatal deaths or stillborns occurred during this study.