The addition of oral piroxicam 40 mg with levonorgestrel increased the efficacy of emergency contraception (EC) in a study conducted in Hong Kong. When used after ovulation, levonorgestrel is not effective, the authors write. COX inhibitors can disrupt follicular rupture after ovulation and thereby increase the action of levonorgestrel. “Piroxicam co-administration could be considered clinically where levonorgestrel EC is the option of choice,” conclude the investigators.
Women at a major community sexual and reproductive health service who needed levonorgestrel EC within 72 hours of unprotected sexual intercourse were block randomized to levonorgestrel 1.5 mg plus either piroxicam 40 mg or placebo orally. Pregnancy results were determined at a follow-up visit 1–2 weeks after the next expected period. An established model was used to assess the number of pregnancies in the piroxicam and placebo groups.
“860 women (430 in each group) were recruited between Aug 20, 2018, and Aug 30, 2022,” the authors write. “One (0.2%) of 418 efficacy-eligible women in the piroxicam group were pregnant, compared with seven (1.7%) of 418 in the placebo group (odds ratio 0.20 [95% CI 0.02–0.91]; P = 0.036). Levonorgestrel plus piroxicam prevented 94.7% of expected pregnancies compared with 63.4% for levonorgestrel plus placebo. We noted no significant difference between the two groups in the proportion of women with advancement or delay of their next period, or in the adverse event profile.”