Randomised comparison between a loading and incremental dose model for ritodrine administration in preterm labour. Effect of terbutaline on premature labor. A double-blind placebo-controlled study. [Tocolysis with hexoprenalin and salbutamol in a clinical comparison]. Isoxuprine and premature labour. Comparison of magnesium sulfate, terbutaline and a placebo for inhibition of preterm labor. A randomized study. Single-centre randomised trial of ritodrine hydrochloride for preterm labour. A double-blind study comparing ritodrine and terbutaline in the treatment of preterm labor. A Danish multicenter study on ritodrine in the treatment of pre-term labour.
To compare a new loading dose regimen for intravenous ritodrine administration in preterm labour with the conventional dose regimen.
                Multicentre randomised trial using numbered opaque sealed envelopes.
                Five teaching hospitals in the Netherlands.
                Women (n = 203) in preterm labour at less than 34 weeks of gestation.
                Women received either a loading dose ritodrine infusion followed, as soon as tocolysis was reached, by a decrease in infusion rate or the conventional schedule of increasing doses until uterine quiescence was achieved.
                Frequency of successful tocolysis (71%) and duration of treatment (55 h) were similar in both groups, but the loading dose schedule was better tolerated with fewer adverse events. Also the number of dose adjustments was smaller than in the incremental dose group (P < 0.001). Overall, the differences between the two regimens were unexpectedly small.
                Despite the small differences, the loading model is easier to apply, requires fewer dose adjustments, is better tolerated with less side effects, and reduces the likelihood of clinical error. The effect of terbutaline, a "selective" beta2-receptor stimulator, was compared with that of placebo in 30 patients in premature labor. Treatment consisted of an intravenous infusion for at least 8 hours, and then of subcutaneous injections four times daily for 3 days together with peroral treatment, which was continued until the end of week 36 of pregnancy. In 12 of 15 terbutaline-treated patients (80 per cent) premature labor was arrested beyond the treatment period, compared with three of 15 in the placebo group (20 per cent). This difference is statistically significant (p less than 0.01). No serious side effects were observed. During infusion, there was an increase in maternal heart rate. This was more pronounced in the terbutaline group (30 per cent) than in the placebo group (9 per cent). There were no adverse effects on blood pressure, but fetal tachycardia was observed more frequently in the terbutaline than in the placebo group. The results suggest that terbutaline is a safe, potent, and well-tolerated inhibitor of premature labor. 140 patients with a threatening premature birth at the greater than or equal to 24-less than 37 week of gestation were in this study randomly treated with hexoprenalin or salbutamol. In 77% in the hexoprenalin and in 74% in the salbutamol group the weight of the newborn was greater than or equal to 2500 g. In 66% in both study groups the birth occurred after the completed 37 weeks of gestation. During infusion of hexoprenalin tachycardia in mothers occurred statistically highly significantly less than during salbutamol. 11% of the mothers in the hexoprenalin group had side-effects during infusion compared to 30% in the salbutamol group. The correlation between the tocolysis-index (Baumgarten) and the prolongation-index (Richter) given by the regression lines facilitates in some measure the comparison of different tocolytic drugs concerning its tocolytic effect. nan Magnesium sulfate has been recommended as a safe and effective agent for inhibiting preterm labor. Its reported adequacy as a tocolytic agent, however, has not been substantiated by randomized, controlled trials. To assess the efficacy of magnesium sulfate, we initiated a prospective, randomized study comparing the capabilities of magnesium sulfate, terbutaline and a placebo (5% dextrose in lactated Ringer's solution) for labor inhibition. The study population consisted of 54 patients between 26 and 34 weeks of gestation and in preterm labor. The diagnosis of labor was made if, following hydration, persistent uterine contractions occurred at a frequency of at least three in a ten-minute period and cervical examination suggested active labor. Success was defined as postponement of delivery for at least 48 hours after initiation of therapy. Despite a trend toward increased efficacy in the terbutaline group there were no significant differences between the three treatment groups with regard to capability of delaying delivery at least 48 hours. Also, there were no significant differences between the groups with regard to gestational age at delivery, birth weight and neonatal survival. The fact that delivery occurred in less than 48 hours of approximately one-half the patients under the best of circumstances emphasizes the need for more effective techniques for the inhibition of preterm labor and the need for a better understanding of the mechanisms involved in the initiation of preterm labor. 106 women between 24 and 33 weeks' gestation and in preterm labour, rigidly defined to include cervical dilatation plus regular uterine contractions, were randomly allocated to receive either intravenous ritodrine hydrochloride or no tocolytic treatment. Ritodrine treatment significantly delayed delivery for 24 hours or less but did not significantly modify the ultimate perinatal consequences of preterm labour. One hundred women in preterm labor were randomly treated with ritodrine or terbutaline in a double-blind fashion. The drugs were comparably effective during intravenous therapy but, in women with intact membranes, an oral dose of terbutaline, 30 mg daily, was significantly more effective than ritodrine, 120 mg daily, in preventing recurrent labor during a 5-day course of oral therapy (one of 19 versus 12 of 23, p less than 0.001). In women with intact membranes, pregnancy was prolonged 40 +/- 25 days (mean +/- SD) in women receiving terbutaline orally and only 22 +/- 24 days in women receiving ritodrine orally (p less than 0.01). In women with intact membranes, a heart rate greater than or equal to 130 bpm occurred in in a higher proportion of women receiving intravenous treatment with ritodrine than among those receiving terbutaline (20 of 31 versus 8 of 27, p less than 0.05). Terbutaline-treated women, however, were significantly more likely to have a serum glucose level in excess of 140 mg/dl than were women treated with ritodrine (13 of 26 versus 6 of 29, p less than 0.05). Side effects commonly observed during intravenous therapy included nausea (22%), chest pain (15%), and shortness of breath (15%). Side effects were significantly (p less than 0.025) more likely to occur during periods when the infusion rate was being increased rather than during periods when the infusion rate was constant. nan
Betamimetics help to delay delivery for women transferred to tertiary care or completed a course of antenatal corticosteroids. However, multiple adverse effects must be considered. The data are too few to support the use of any particular betamimetics.
[Note: The 14 citations in the awaiting classification section of the review may alter the conclusions of the review once assessed.]