The common painkiller ibuprofen may boost heart attack risk by blocking the lifesaving effects of aspirin, a new study shows.
"The public health impact of this is monstrous," Michael Farkouh, director of clinical trials at Mount Sinai Heart, a premier New York cardiovascular centre has said.
"Ibuprofen is relatively safe except when we give it with aspirin to people at high risk of heart attack," Farkouh says. "But when given with aspirin, we do we see an excess of heart attacks."
This is a controversial conclusion. The study itself had not been designed to look at ibuprofen safety, nor has it proved that ibuprofen is harmful to people at high risk of heart disease.
But it does provide a clear warning sign that ibuprofen is risky for people who need the blood-clot-reducing effect of daily low-dose aspirin.
Those taking aspirin in the ibuprofen arm of the study had a ninefold excess of heart attacks.
But another expert Steve Nissen, chairman of cardiovascular medicine at The Cleveland Clinic and past president of the American College of Cardiology, urges caution. He notes that the findings are based on only eight heart attacks among thousands of high-risk patients taking ibuprofen and aspirin.
Still Dr.Farkouh says the numbers may be small but the potential risks are great. And it would not be the first time that relatively small numbers of heart attacks caused a major change in how doctors look at pain drugs.
"The whole Vioxx thing was based on 64 heart events among 21,000 patients studied," Farkouh recalls. "Here we are talking about potentially a higher magnitude of impact. The interaction of ibuprofen with aspirin is a bigger public health concern than Vioxx was."
Rofecoxib, a nonsteroidal anti-inflammatory drug, was marketed under the brand name Vioxx by Merck for treatment of osteoarthritis, and related acute pain conditions.
Worldwide, over 80 million people were prescribed rofecoxib at some time.
On September 30, 2004, Merck voluntarily withdrew rofecoxib from the market because of concerns about increased risk of heart attack and stroke associated with long-term, high-dosage use. Rofecoxib was one of the most widely used drugs ever to be withdrawn from the market.
The study by Farkouh and colleagues enrolled 18,325 arthritis patients. Nearly 17% of these patients were at high risk of heart attack and stroke.
The trial compared ibuprofen (brand names include Advil, Motrin, and Nuprin) or naproxen (Aleve, Naprosyn) to a new pain drug sold as Prexige in the U.K. and Canada.
All of the high-heart-risk patients in the Farkouh study should have been taking low-dose aspirin. Sixty percent of them did. These patients should have had fewer heart attacks, strokes, and heart deaths than those who did not take aspirin.
But if the patients took aspirin and also took high-dose ibuprofen, they were nine times more likely to have a heart attack than were patients who took aspirin and Prexige. Patients who took ibuprofen without taking aspirin were no more likely to have a heart attack than those who took Prexige.
While there is strong evidence that ibuprofen blocks the blood-clot-preventing effects of aspirin, still the drugs do not interact if a person takes aspirin two hours before taking ibuprofen. But whether such a practice will work in real life situations is a different question altogether.
One more trial to finally solve the question of Ibuprofen risk is on, but the study won't start returning results until 2010.