Taking the morning after pill with a 30p painkiller ‘could make it 50% more effective’
THE morning after pill could be 50 per cent more effective when taken with a painkiller, according to a new study.
Scientists called the findings, which are the first of their kind, “really exciting”.
There are two types of emergency contraceptive pills in the UK – Levonelle (levonorgestrel) and ellaOne (ulipristal acetate).
Both work by preventing or delaying ovulation and neither are effective post-ovulation.
The earlier a woman takes them after unprotected sex, the better.
The new study, published in The Lancet, took place at a sexual health clinic in Hong Kong between August 2018 and August 2022.
Women who required the morning after pill were randomly assigned to receive either piroxicam or a dummy pill in addition to levonorgestrel.
Piroxicam is an anti-inflammatory drug costing around 30 to 40p per tablet.
It is used for pain, tenderness and swelling caused by arthritis, which affects 10 million people in the UK.
A follow-up appointment was scheduled one to two weeks after the womens’ next expected period and, if a normal period had not occurred by that time, a pregnancy test was carried out.
Researchers calculated the proportion of pregnancies prevented “out of those expected” using an established model published in 1998.
There was one pregnancy among the 418 women who took piroxicam and levonorgestrel, and seven pregnancies among the 418 women who had the dummy pill and levonorgestrel.
The percentage of pregnancies prevented with the piroxicam-levonorgestrel treatment was 95 per cent, compared with 63 per cent in those who took levonorgestrel alone.
The researchers say that if their findings can be reproduced in the future, clinical guidelines should change.
Manufacturers have shown that Levonelle is 95 per cent effective within one day of unprotected sex, 85 per cent after two days, and 58 per cent after three days.
Dr Sue Lo, from the Family Planning Association of Hong Kong, a co-investigator of the study, said: “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.”
First author of the study Dr Raymond Li, from the University of Hong Kong, added: “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.”
While Dr Janet Barter, president of the Faculty of Sexual and Reproductive Healthcare, said: “We welcome the findings of this new study which has the potential to improve the efficacy of emergency contraception, which is very exciting.”
She added the emergency copper intrauterine device (IUD) – which is the most effective – is also available for women in the UK needing emergency contraceptive.
Dr Janet Nooney, expert scientific assessor in the MHRA benefit risk management unit, said: “This study raises an interesting possible improvement in emergency contraceptive…
“Importantly, in the UK oral piroxicam tablets are no longer recommended for acute pain relief or inflammatory conditions as it is associated with serious gastro-intestinal side effects and rare but possibly fatal skin reactions.
“These side effects may limit its suitability for wider use in combination with emergency contraception.”
There were no differences in side effects between the women who took piroxicam and those who didn’t in this study.
Dr Nooney said that further work would be needed to bolster the evidence, including on women of a higher weight, who the morning after pill does not work as well for.
Writing in a separate commentary in The Lancet, Erica Cahill, from the Stanford University School of Medicine, cautioned that the study participants were mostly of Asian ethnicity and weighed less than 70kg (11st or 154lbs).
The improved effectiveness “might not be generalisable to patients with higher BMIs”, she said.