New Study Shows Combined Treatment of Piroxicam and Levonorgestrel Emergency Contraceptive is More Effective in Preventing Pregnancies
A recent study published in The Lancet has found that combining the anti-inflammatory medication piroxicam with the levonorgestrel emergency contraceptive pill significantly increases its efficacy in preventing pregnancies compared to levonorgestrel alone. The research revealed that 95% of pregnancies were prevented with the combined treatment, while only 63% were prevented with levonorgestrel alone.
Emergency contraceptive pills containing either levonorgestrel or ulipristal acetate are widely used around the world. Levonorgestrel is available in more countries than ulipristal acetate and is one of the most popular choices for emergency contraception. Both pills work by preventing or delaying ovulation and are not effective after ovulation has occurred.
The effectiveness of levonorgestrel has been based on a trial conducted in 1998, which showed that it prevented 95% of expected pregnancies when taken within 24 hours of unprotected sex. However, more recent research suggests that its efficacy might be lower than previously thought.
The study conducted in Hong Kong involved women who required levonorgestrel emergency contraception within 72 hours of unprotected sex. They were randomly assigned to receive either a single supervised dose of levonorgestrel 1.5 mg plus piroxicam 40 mg or a placebo pill. The participants and healthcare professionals were unaware of which treatment group they belonged to. A follow-up appointment was scheduled after the next expected period to assess the outcomes.
Among the 836 women followed up, there was only one pregnancy in the group that received piroxicam and levonorgestrel, while there were seven pregnancies in the group that received the placebo and levonorgestrel. The percentage of pregnancies prevented following the combined treatment was 95%, compared to 63% in the levonorgestrel alone group.
The study also found that there were minimal differences in the rates of side effects between those receiving piroxicam and placebo co-treatment.
Dr. Sue Lo from the Family Planning Association of Hong Kong, a co-investigator of the study, expressed excitement about the findings, stating that the discovery of a widely available medication that increases levonorgestrel’s efficacy is significant. Dr. Raymond Li, the first author of the study, added that this is the first study to suggest that a safe and readily available medication taken with levonorgestrel can prevent more pregnancies than levonorgestrel alone. The researchers hope that these results will lead to further research and changes in clinical guidelines to improve access to more effective emergency contraception worldwide.
However, the study has some limitations, including the need for further research to understand piroxicam’s mechanism of action and its applicability to diverse populations. The findings may not be generalizable to all patients, as the study focused on a specific population mainly of Asian ethnicity and with a lower body weight.
Overall, this study highlights the potential of combining piroxicam with the levonorgestrel emergency contraceptive pill to enhance its effectiveness in preventing pregnancies. Future research will be necessary to validate these findings and improve emergency contraception options for women globally.
Reference: “Oral emergency contraception with levonorgestrel plus piroxicam: a randomised double-blind placebo-controlled trial” by Raymond Hang Wun Li, Sue Seen Tsing Lo, Kristina Gemzell-Danielsson, Carol Ho Yi Fong, Pak Chung Ho and Ernest Hung Yu Ng, 16 August 2023, The Lancet.
DOI: 10.1016/S0140-6736(23)01240-0
The study was funded by the Department of Obstetrics and Gynaecology at The University of Hong Kong.