1. Levonorgestrel plus piroxicam resulted in significantly fewer pregnancies compared to placebo.
2. There were no changes with respect to menstrual cycle advancement or delay in each group.
Evidence Rating Level: 1 (Excellent)
Study Rundown: Levonorgestrel is a commonly used emergency contraceptive; however, its therapeutic benefits require it to be used prior to ovulation. Whether or not the addition of a cyclo-oxygenase inhibitor, such as piroxicam, could enhance the efficacy of emergency contraception beyond the ovulatory window remains unclear. This randomized controlled trial aimed to investigate if adding piroxicam to levonorgestrel could improve the efficacy of emergency contraception within 72 hours of unprotected sexual intercourse. The primary outcome was the proportion of pregnancies prevented versus those expected based on a model, while the key secondary outcomes were changes in menstrual periods. According to study results, piroxicam plus levonorgestrel significantly improved the efficacy of emergency contraception. Although this study was well done, it only included patients from a specific demographic, thus reducing its validity.
In-depth [randomized-controlled trial]: Between Aug 20, 2018, and Aug 30, 2022, 4583 patients were screened for eligibility across a sexual health clinic in Hong Kong. Included were women ≥ 18 years old having emergency contraception within 72 hours of sexual intercourse and menstruating every 24-42 days. Altogether, 860 women (430 each in placebo and levonorgestrel plus piroxicam) were included in the study. The primary outcome of prevented pregnancies was greater in the levonorgestrel plus piroxicam group (94.7%) compared to levonorgestrel plus placebo (63.4%). Fewer patients in the piroxicam group became pregnant than the placebo group (0.2% vs. 1.7%, odds ratio [OR] 0.20, 95% confidence interval [CI] 0.02-0.91, p=0.036). There were no changes between groups with respect to the secondary outcome of menstrual cycle advancement or delay. Overall, findings from this study suggest that co-administration of piroxicam with levonorgestrel improves efficacy of emergency contraception.
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