A randomised controlled study comparing Drotaverine hydrochloride and Valethamate bromide in the augmentation of...

Cervical dilatation is a poorly understood process. Various drugs have been used to facilitate this process and reduce the duration of labour and thereby reduce feto-maternal complications. The present study is an attempt to compare and evaluate the efficacy of Drotaverine hydrochloride and Valethamate bromide in the process of cervical dilatation and labour augmentation.

A prospective randomised trial of 146 low-risk women in spontaneous labour was conducted. 49 women were given Drotaverine (Group 1), 49 women were given Valethamate (Group 2) and 48 women were given placebo (Group 3). At 4 cm of cervical dilatation, elective amniotomy was done and the injection was given intramuscularly, and repeated every hour for a maximum of three doses.

There was a statistically significant difference in the mean injection-delivery times (time from first injection to delivery of the baby), which was 183.2 min (SD 78.8) in the Drotaverine group compared to 206.5 min (SD 69.7) in the Valethamate group, and 245 min (SD 70.9) in the control group. The mean cervical dilatation rate (cm/h) was 3 (SD 1.4), 2.4 (SD 0.9) and 1.9 (SD 0.6) in groups 1, 2 and 3, respectively, and these differences were statistically significant. There were no statistically significant differences in the duration of second and third stage of labour. Transient side effects such as foeto-maternal tachycardia, flushing of the face and dryness of mouth were noted with Valethamate. A few patients complained of headache in the Drotaverine group.

Both Drotaverine and Valethamate appear to significantly help cervical dilatation and augment first stage of labour. But, Drotaverine is superior to Valethamate with fewer side effects.