Efficacy and Safety of Drotaverine Hydrochloride Versus Placebo in Primigravida Women Undergoing Labor: A Systematic Review and Meta-Analysis.

BACKGROUND: The active phase of labor may be prolonged due to excessive cervical smooth muscle spasms, which hinder natural dilation. Drotaverine hydrochloride, a selective phosphodiesterase-4 (PDE-4) inhibitor with smooth muscle relaxant properties, has gained interest as a labor-augmenting agent. This study evaluates its effects on labor duration, maternal and neonatal safety, and comparative efficacy. METHODS: A systematic review and meta-analysis was conducted using PubMed, Embase, and the Cochrane Library. Eligible studies were English-language RCTs comparing drotaverine with placebo in nulliparous women at ≥ 28 weeks' gestation with singleton pregnancies. Primary outcomes were labor duration and cervical dilation rate; secondary outcomes included maternal side effects, neonatal Apgar scores, NICU admission, birth weight, delivery mode, and oxytocin use. Data extraction and risk of bias assessment were performed independently by two reviewers. Statistical analysis was conducted via RevMan 5.4. RESULTS: Four RCTs (n = 825; drotaverine: 415, placebo: 410) were included. Drotaverine significantly increased cervical dilation (MD 0.91 cm/h; 95% CI, p < 0.0001) and shortened the active first stage of labor (MD 95.68 min; 95% CI, -146.13 to -45.22; p = 0.0002). It reduced pain at 30 min post-administration, as assessed using the visual analog scale (VAS) (MD 2.22; p = 0.007) but showed no significant effect on later stages, maternal or neonatal outcomes. CONCLUSION: Drotaverine may enhance cervical dilation and reduce active labor duration with short-term pain relief, without adverse maternal or neonatal effects. Larger studies are needed to confirm long-term safety and comparative effectiveness.