Levonorgestrel and Anti-Inflammatory Medications Combo for Emergency Contraception

Taking piroxicam, an anti-inflammatory medication commonly used for arthritis pain, at the same time as the levonorgestrel emergency contraceptive pill after unprotected sex prevents significantly more pregnancies compared to taking levonorgestrel alone, according to a randomized controlled trial published in The Lancet.

Two types of emergency contraceptive pills - containing either levonorgestrel or ulipristal acetate - are the most widely used emergency contraception method in most countries. The accepted effectiveness of levonorgestrel is based on the results of a trial from 1998 in which levonorgestrel prevented 95% of expected pregnancies when taken within 24 hours of unprotected sex, 85% if taken within 25–48 hours, and 58% if taken within 49–72 hours. However, more recent research suggests the efficacy of levonorgestrel might be lower.

The study took place at a major community sexual and reproductive health service in Hong Kong between August 2018 and August 2022. Women who required levonorgestrel emergency contraception within 72 hours of unprotected sex were randomized to receive a single supervised dose of levonorgestrel 1.5 mg plus either piroxicam 40 mg or a placebo pill.

Of the 836 women followed up, there was one pregnancy among the 418 women who took piroxicam and levonorgestrel and seven pregnancies among the 418 women who had the placebo and levonorgestrel. The percentage of expected pregnancies without contraception was estimated at 4.5% in both groups. Therefore, the percentage of pregnancies prevented following piroxicam- levonorgestrel co-treatment was 95% , compared with 63% in those who took levonorgestrel and placebo.

Reference: Oral emergency contraception with levonorgestrel plus piroxicam: a randomized double-blind placebo-controlled trial, The Lancet, DOI: https://doi.org/10.1016/S0140-6736(23)01240-0