Ritodrine hydrochloride: a betamimetic agent for use in preterm labor. I. pharmacology, clinical history, administration, side effects, and safety.

Ritodrine hydrochloride has become the first drug approved in the United States specifically for use in preterm labor. The drug is a beta-sympathomimetic agent with predominant effects upon beta 2 receptors of the uterus. In this report, the pharmacology, distribution, disposition, and excretion are briefly reviewed. Recommendations for selecting patients most likely to benefit from ritodrine are given, together with the dosage and administration schedules that have been found most effective. Although this drug is not without side effects, it has been more thoroughly evaluated in prospective double-blind controlled trials than any of the other agents commonly used in preterm labor. In comparison with these agents, it seems relatively safe and the side effects are usually well tolerated. Part 2 of the paper discusses the evidence for efficacy.