The effect of relcovaptan (SR 49059), an orally active vasopressin V1a receptor antagonist, on uterine contractions in preterm labor.

Relcovaptan (SR 49059) is a non-peptide, orally active vasopressin V1a receptor inhibitor. The effect on uterine contractions in 18 women with preterm labor in pregnancy weeks 32-36 was assessed in a double-blind investigation. The inclusion criterion was at least four regular uterine contractions over 30 min as measured by external tocodynamometry. Twelve patients received at random a single oral dose of 400 mg relcovaptan and six received placebo, and contractions were monitored up to 6 h thereafter. Rescue medication (beta-adrenoceptor-stimulating drug) was allowed after 2 h. Before drug administration a mean (+/- SE) of 8.2 +/- 1.4 and 9.7 +/- 1.6 contractions/30 min were recorded in the relcovaptan- and placebo-treated groups, respectively. In the former group, the frequency of uterine contractions started to decrease within the first half hour, and 1.5-2 h after dosing it was steady at 3.2 +/- 0.9 contractions/30 min. Correspondingly, after placebo, 7.8 +/- 2.2 contractions/30 min were recorded, a statistically significant difference (p = 0.017). The activity in the relcovaptan-treated women remained low, whereas in the placebo group inhibited uterine contractions were observed only in women receiving 'rescue' tocolytic treatment. It is concluded that relcovaptan inhibits preterm labor.

RCT Entities:   Population Interventions Outcomes