Anti-inflammatory could boost emergency contraceptive: Study

The results of a randomised controlled trial suggest that the emergency contraceptive levonorgestrel could be more effective when taken alongside piroxicam, an anti-inflammatory medication often used for arthritic pain.
 
The results of the study, carried out by University of Hong Kong researchers, were published this month in The Lancet.
 
The participants were women who requested emergency contraception at a community sexual health service in Hong Kong over four years from August 2018 to August 2022.
 
Those who needed emergency contraception within 72 hours of unprotected sex were given a 1.5 mg dose of levonorgestrel, then either 40 mg of piroxicam or a placebo.
 
Nearly 840 women were followed up, evenly split between those who took piroxicam and those who took the placebo.
 
Neither the participants nor the healthcare professionals knew which treatment they had.
 
There was one pregnancy among the 418 participants who took piroxicam along with levonorgestrel, while there were seven pregnancies among the 418 women in the placebo group.
 
According to data used by researchers as a benchmark, the number of pregnancies expected without contraception is estimated at 4.5%, which would translate to 19 out of 418 women.
 
They calculated that 95% of pregnancies (18 out of 19) were prevented in the group using piroxicam and levonorgestrel, compared to 63% (12 out of 19) in the levonorgestrel and placebo group. 
 
‘Oral piroxicam 40 mg co-administered with levonorgestrel improved efficacy of emergency contraception in our study,’ the authors wrote.  
 
‘Piroxicam co-administration could be considered clinically where levonorgestrel emergency contraception is the option of choice.’

Dr Sue Lo, a co-investigator of the study who also works for the Family Planning Association of Hong Kong, was impressed by the results.
 
‘The levonorgestrel emergency contraceptive pill is one of the most popular choices of emergency contraception in many parts of the world, so finding out that there is a widely available medication which increases levonorgestrel’s efficacy when they are taken together is really exciting,’ she said.
 
Dr Raymond Li from The University of Hong Kong, a co-author of the research, said the study is the first to suggest another medication taken at the same time as levonorgestrel could prevent more pregnancies than levonorgestrel on its own.
 
‘We hope these results will lead to further research and ultimately changes in clinical guidelines to enable women around the world to access more effective emergency contraception,’ he said.

Another co-investigator, Professor Kristina Gemzell-Danielsson from the Karolinska Institute, said piroxicam might work by targeting prostaglandins.  
 
‘Prostaglandins facilitate several reproductive processes including ovulation, fertilisation, and embryo implantation,’ she said.
 
‘Therefore, we speculate that piroxicam may provide a contraceptive effect both pre-ovulation [by blocking the ovulatory process] and post-ovulation [by preventing the implantation of the embryo].’
 
She said the trial did not investigate the mechanism of action, and that further study is needed.
 
The research excluded women who had recently used hormonal contraception, and those who had unprotected sex more than once before taking the emergency contraception.
 
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