While both atosiban and hexoprenaline are effective for halting uterine contractions during fetal distress, atosiban seems to cause fewer maternal adverse events, faster resumption of contractions (8 vs. 14 minutes, respectively), and can be given faster as an IV bolus (1 vs. 5 minutes, respectively), according to a prospective, randomized pilot trial.
Austrian researchers studied 1,431 women with singleton, cephalic presentation, term pregnancies. Tocolysis was achieved in 92% of the atosiban group and in 100% of the hexoprenaline group. Only one woman in the atosiban group showed no reaction to the drug, which could be due to the fact that the drug was administered during the second stage of labor; all other women receiving the agent received it during the first stage.
Afschar P, Scholl W, Bader A, et al. A prospective randomized trial of atosiban versus hexoprenaline for acute tocolysis and intrauterine resuscitation. BJOG. 2004;111:316-318.