Health Canada wishes to inform Canadians of safety concerns regarding the group of drugs known as selective COX-2 inhibitor NSAIDs (non-steroidal anti-inflammatories). These include Vioxx (rofecoxib), which has been withdrawn from the market, Celebrex (celecoxib), Bextra (valdecoxib), and Mobicox (meloxicam), which are used in the treatment of symptoms of rheumatoid arthritis, osteoarthritis and primary dysmenorrhea (menstrual pain).
Accumulating evidence indicates that the use of selective COX-2 inhibitor NSAIDs, in certain individuals, is associated with an increased risk of heart attack or stroke when compared to placebo. The risk appears to increase with the total daily dose and the length of the treatment. However, given the available data, it is not possible to identify which patients would present a higher risk of heart attack and stroke.
Health Canada has requested additional safety information from the manufacturers of CelebrexÂ®, BextraTM, MobicoxÂ® and generic forms of meloxicam, and will continue to review the safety profile of these drugs in order to fully consider what is presently known about the risks and benefits of these drugs when used according to their labelling.
Until further information from long-term clinical trials becomes available, one should consider that there is a strong possibility of an increased risk of cardiovascular events, including heart attack and stroke, when using selective COX-2 inhibitor NSAIDs (Celebrex, Bextra, Mobicox, and all generic forms of meloxicam).
Patients should discuss the benefits and risks of treatment options with their physician, in light of the following information.
Vioxx was withdrawn on September 30, 2004, based on new safety information from a three-year, randomized double-blind clinical trial, called APPROVe, showing a possible increased risk of cardiovascular events. The APPROVe (Adenomatous Polyp Prevention on VIOXX) clinical trial was designed to assess the effectiveness of 25 mg Vioxx in preventing the recurrence of colon polyps (abnormal tissue growth, which may or may not be cancerous). In the APPROVe trial, Vioxx was compared to a placebo (sugar pill). Merck & Co withdrew Vioxx from the worldwide market after the study indicated an increased risk of serious cardiovascular events, such as heart attacks and strokes, after 18 months of continuous treatment.
On December 10, 2004, Pfizer Inc. released new information about cardiovascular risks associated with Bextra. In a study conducted by Pfizer, which included over 1,500 patients treated for acute pain after coronary artery bypass grafting (CABG), an increased risk of cardiovascular events was observed in patients treated with BextraTM compared to placebo. These cardiovascular events included myocardial infarction (heart attack), cerebrovascular accident (stroke), deep vein thrombosis (blood clots in the leg), and pulmonary embolism (blood clot in the lung). The risk of these effects was observed to be greater with the intravenous form of the drug (approximately two percent of patients had such an adverse event), in comparison with the oral form of the drug (approximately 1 percent of patients), immediately following CABG surgery. About 0.5 percent of patients taking the placebo had an adverse cardiovascular event.
On December 17, 2004, the National Cancer Institute (NCI) in the United States announced that it had stopped a three-year Celebrex study called Adenoma Prevention with Celecoxib (APC) due to an interim analysis showing a statistically significant increase in the risk of heart attack, stroke and cardiovascular death. Health Canada has withdrawn market authorization for the use of CelebrexÂ® for the prevention of recurrence of Familial Adenomatous Polyposis, which is predictive of colorectal cancer. Celebrex should not be taken for the prevention of recurrence of Familial Adenomatous Polyposis and patients should discuss alternative therapeutic options with their doctors.
Background on Selective COX-2 Inhibitor NSAIDs
Selective COX-2 inhibitor NSAIDs were first authorized for sale in Canada in 1999 based on data showing a better gastrointestinal safety profile than traditional (non-selective) NSAIDs (for example, ibuprofen). There was a need for new therapies because of the well-documented frequent and severe gastro-intestinal adverse events (for example ulcers and gastric haemorrhages) associated with the use of traditional (non-selective) NSAIDs. Also, a significant number of patients could not tolerate traditional (non-selective) NSAIDs because of stomach upset.
It should be noted that alternative therapies to selective COX-2 inhibitor NSAIDs also present risks. Therefore, patients should discuss with their physician all benefits and risks of selective COX-2 inhibitor NSAIDs versus alternative therapies, in order to determine the most appropriate treatment in their individual case.