The effect of non-steroidal anti-inflammatory drugs on medical abortion with mifepristone and misoprostol at 13-22 weeks gestation

BACKGROUND: Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit the biosynthesis of prostaglandins and concerns have been expressed that they might attenuate the effects of exogenous prostaglandins. This randomized study was conducted to evaluate whether NSAID given during medical abortion with mifepristone/misoprostol in the second trimester has a negative effect on the efficacy of the abortifacient by prolonging the induction-to-abortion interval. METHODS: Seventy-four women were treated with the anti-progesterone mifepristone, followed by repeated doses of misoprostol 36-48 h later. They were randomized to receive a prophylactic pain treatment of either paracetamol and codeine or diclofenac with the first dose of misoprostol. RESULTS: Co-treatment of NSAID with misoprostol did not attenuate the efficacy of mifepristone and misoprostol. There was no significant difference between the NSAID and the non-NSAID group in the induction-to-abortion interval (5.4 versus 6.5 h) or the total doses of misoprostol needed (2 versus 3). The frequency of surgical intervention was similar (55.6 versus 52.6%). Women in the group treated with NSAID required significantly less opiates (P = 0.042). CONCLUSION: Co-treatment with NSAID and misoprostol does not interfere with the action of mifepristone and/or misoprostol to induce uterine contractions and pregnancy expulsion in medical abortion. Prophylactic NSAID administration reduces the need for opiate injections.