Drotaverine hydrochloride vs. valethamate bromide in acceleration of labor.

Objectives: To compare the efficacy and safety of drotaverine hydrochloride and valethamate bromide in shortening the duration of labor.
Methods: In a randomized controlled trial of 150 nulliparous women in established labor with cervical dilation of 4 cm, 50 women were given drotaverine (group I), 50 women were given valethamate (group II) and another 50 women were not given any medication (group III). Duration of labor, mode of delivery, side effects, and neonatal outcome were measured in all cases. Appropriate non-parametric tests and chi(2) tests were used for assessment of statistical significance.
Results: In the three groups, 100%, 96% and 46% women delivered within 6 h, respectively. The injection-to-delivery interval was significantly reduced in the drotaverine group (193.96 min) in contrast to the valethamate group (220.68 min) and control group (412.84 min). The rate of cervical dilation was highest in the drotaverine group (2.04 cm/h) compared with the valethamate bromide group (1.86 cm/h) and control group (1.01 cm/h). There were no major maternal or fetal adverse effects in any group, but minor side effects were more common in the valethamate group.
Conclusion: Both intramuscular drotaverine hydrochloride and valethamate bromide are effective in acceleration of labor; however, drotaverine accelerates labor more rapidly and is associated with less side effects.