Clinical practice evaluation of combination of atosiban, ritodrine and ketoprofen for inhibiting preterm labor

Abstract

Aim: The aim of this study was to compare the efficacy and tolerability of atosiban vs ritodrine administered as single-drug or as combination therapy with the COX inhibitor ketoprofen in the treatment of preterm labor and to investigate how frequent is the need for combination therapy with ketoprofen.

Methods: Ninety-one women with diagnosis of threatened preterm delivery at 24-33 weeks' gestation were enrolled in an observational case-control study. Forty-seven received IV atosiban (6.75 mg initial dose, 300 microg/min loading dose for 3 hours, 100 microg/min maintenance dose for 48-96 hours) and 44 IV ritodrine (0.05-0.3 mg/min). When response to the first drug in the first 2-4 hours was unsatisfactory, ketoprofen was added (100 mg loading dose IV and 100-150 mg maintenance dose every 12 hours) for a maximum of 48 hours.

Results: Ketoprofen was added in 51.1% of the atosiban group and 47.7% of the ritodrine group (P 0.75, not statistically significant). The percentages of women non delivered in the two groups were 85.1% vs 81.8% at 48 hours (P=0.44) and 59.6% vs 54.5% at 7 days (P=0.39). One woman treated with atosiban reported transient dyspnea at the administration of the bolus dose; 20.5% of women who received ritodrine developed tachycardia and 4.5% dyspnea (P=0.001). Neonatal mortality and morbidity were comparable in both groups and unrelated to ketoprofen exposure.

Conclusion: Atosiban efficacy was comparable to ritodrine, but with a superior safety profile. A large proportion of women in both groups required second-line ketoprofen therapy, with comparable neonatal outcomes.