Women on the pill who also take popular over-the-counter painkillers are more likely to suffer potentially fatal blood clots, warns new research.
Using non-steroidal anti-inflammatory drugs (NSAIDs) such as Nurofen alongside hormonal contraception leads to an increased risk of blood clots, according to the Danish study published by The BMJ.
The risk was greater in women using combined oral contraceptives containing third or fourth-generation progestins but smaller in women using progestin-only tablets, implants and coils, alongside NSAIDs ibuprofen, diclofenac and naproxe.
The research team stressed that the absolute risk of developing a serious blood clot is low, even in women using high-risk hormonal contraception.
But given the widespread use of both hormonal contraception and NSAIDs, they say women should be advised of the potential risk.
NSAIDs have previously been linked to blood clots, but little is known about whether using them influences the risk of blood clots, also known as venous thromboembolism, in otherwise healthy women using hormonal contraception.
The Danish research team used national medical records to track first-time diagnoses of blood clots among two million women aged 15 to 49 living in Denmark between 1996 and 2017 with no history of blood clots, cancer, hysterectomy or fertility treatment.
Hormonal contraception was divided into high, medium and low risk, according to their association with VTE based on previous studies.
High-risk hormonal contraception included combined estrogen and progestin patches, vaginal rings, and pills containing either 50 mcg estrogen or third or fourth-generation progestins.
Medium-risk contraception included all other combined oral contraceptives and the medroxyprogesterone injection, while progestin-only tablets, implants, and hormone intrauterine devices (coils) were classed as low or no risk.
A range of potentially influential factors, such as age, education level, pregnancy history, prior surgery, high blood pressure and diabetes, were also taken into account.
NSAIDs were used by more than half-a-million women while using hormonal contraception. Ibuprofen was the most frequently used NSAID (60 percent), followed by diclofenac (20 percent) and naproxen (6 percent).
Over an average 10-year monitoring period, 8,710 venous thromboembolic events occurred and 228 women (2.6 percent) died within 30 days of their diagnosis.
NSAID use was associated with four extra venous thromboembolic events per week per 100,000 women not using hormonal contraception, 11 extra events in women using medium-risk hormonal contraception, and 23 extra events in women using high-risk hormonal contraception.
Among individual NSAIDs, the association was strongest for diclofenac compared with ibuprofen and naproxen.
Study author Dr. Amani Meaidi, of the University of Copenhagen, said: “Using high quality, linkable, national registries, this nationwide study adds new knowledge on the risk of a potentially fatal event during concomitant use of two drug classes often prescribed to otherwise healthy women.
“Women needing both hormonal contraception and regular use of NSAIDs should be advised accordingly.”
Dr. Morten Schmidt, of Aarhus University Hospital, said the findings raise “important concerns” about using NSAIDs, particularly diclofenac, and high-risk hormonal contraception at the same time.
He suggests that health authorities should include the findings in their safety assessment of available over-the-counter diclofenac, while women using the pill and their doctors should consider alternatives to NSAIDs for analgesia.
Dr. Schmidt added: “If treatment with NSAIDs is needed, agents other than diclofenac seem preferable, along with lower-risk hormonal contraceptives such as progestin-only tablets, implants, or intrauterine devices.”
Produced in association with SWNS Talker