In vitro study of phosphodiesterase-inhibiting drugs: a complement to beta-sympathomimetic drug therapy in premature labor?

Since terbutaline treatment in premature labor has been shown to increase phosphodiesterase activity in the myometrium, the phosphodiesterase-inhibiting effect of theophylline and papaverine on myometrial preparations from pregnant women has been studied. The patients were either treated with terbutaline during the last 3 weeks of pregnancy or not treated. The results showed that papaverine is about 100 times more potent than theophylline in both phosphodiesterase-inhibiting effect and muscle-relaxing effect. No differences in effects were found in myometrial strips from terbutaline-treated or untreated women. A possible improvement in the tocolytic therapy with a combination of a beta-sympathomimetic and a phosphodiesterase-inhibiting drug is suggested.