Drotaverine to shorten the duration of labour in primigravidas: a randomised, double-blind, placebo-controlled trial

BACKGROUND: Drotaverine, a spasmolytic, has been found to have potential to achieve a reduction in the duration of labour and prevent prolonged labour. OBJECTIVE: To compare the effects of intravenous drotaverine hydrochloride with placebo for shortening the duration of active phase of labour in primigravidas. METHODS: A double-blind, placebo-controlled randomized trial of 246 primigravidas in active phase of labour at term was conducted. They were randomly (1:1 ratio) administered intravenous 2 ml (40mg) of drotaverine hydrochloride or 2 ml of Vitamin B complex as placebo. The primary outcome measure was the duration of active phase of labour. The secondary outcome measures were cervical dilatation rate, oxytocin augmentation rate, incidence of prolonged labour, labour pain scores, mode of delivery, maternal and neonatal outcomes. RESULTS: The mean duration of active phase of labour (hour) was significantly lower in the drotaverine group compared to the control (drotaverine; 6.22 ± 2.41 vs placebo; 8.33 ± 3.56; p <0.001). Also, the cervical dilatation rate (cm/hr) was significantly faster in the drotaverine arm (drotaverine; 1.68 ± 1.02 versus placebo; 1.06 ± 0.53, p <0.001). There was a significantly higher probability of faster delivery among women who were given drotaverine (log-rank test, p < 0.001). The oxytocin augmentation rate, incidence of prolonged labour, labour pain scores, mode of delivery, maternal and neonatal outcomes were not significantly different among the groups. CONCLUSIONS: Drotaverine hydrochloride is effective in shortening the duration of active phase of labour without adverse maternal and neonatal outcomes. However, more evidence is needed to explore its role in active phase of labour among primigravid women. Trial registration number: PACTR201810902005232.