Double-blind evaluation of ritodrine sustained release for oral maintenance of tocolysis after active preterm labour.

Objective: To evaluate the effect of ritodrine sustained release capsules for maintaining uterine quiescence after successful treatment of active preterm labour.

Design: Multicentre placebo-controlled trial.

Setting: Five teaching hospitals in the Netherlands.

Randomised comparison between a loading and incremental dose model for ritodrine administration in preterm labour.

Objective: To compare a new loading dose regimen for intravenous ritodrine administration in preterm labour with the conventional dose regimen.

Design: Multicentre randomised trial using numbered opaque sealed envelopes.

Setting: Five teaching hospitals in the Netherlands.

A loading model for ritodrine administration in preterm labour.

Objective: To develop a ritodrine infusion scheme for preterm labour that avoids plasma levels above those needed for tocolysis, requires only one rate adjustment, and is easy to apply in practice.

Design: Prospective study of tocolytic effect and plasma ritodrine concentrations during application of the infusion scheme.

Setting: High risk labour ward.

A loading-dose infusion scheme for intravenous tocolysis with ritodrine: a pilot study.

A loading-dose infusion scheme for intravenous ritodrine therapy was tested in twelve patients with preterm labour. We started with a rather high (386 micrograms/min) infusion rate, but the moment tocolysis was reached this infusion rate was reduced to a level needed to maintain the plasma concentration then found. Plasma samples of ritodrine were taken the moment tocolysis was reached and in the steady state, and compared with each other and with expected and calculated plasma concentrations.

A new administration form of ritodrine. Ritodrine plasma levels with sustained-release capsules in a steady state.

A sustained-release administration form of oral ritodrine was introduced to cope with the problem of the short dosage interval inherent to conventional oral ritodrine administration. The bioavailability of this application form was assessed in a clinical study including 11 patients. With a dosage frequency of only 3 times daily and a dosage form index of 1.