Low-dose anti-inflammatory drugs such as Celebrex don't seem to be as dangerous as Vioxx for seniors with no history of heart attacks, a Montreal study suggests.

McGill University researchers, who tracked nearly 114,000 Quebecers aged 66 or older, found that low-risk patients who used Celebrex suffered no heightened risk of heart attack.

Celebrex, known generically as celecoxib, belongs to the same drug family of COX-2 inhibitors as Vioxx, which was pulled off the market last fall by manufacturer Merck & Co. after studies linked it to heart problems.

Celebrex, a popular arthritis drug, is only one-tenth as potent with certain COX-2 enzymes as Vioxx.
Celebrex, a popular arthritis drug, is only one-tenth as potent with certain COX-2 enzymes as Vioxx.

"No increased risks were observed with celecoxib," says the McGill University Health Centre study, published Feb. 1 in the online edition of the Annals of Internal Medicine.

The risk of heart attack jumped by 24 per cent for users of Vioxx who hadn't previously suffered a heart attack, indicated the study, corroborating previous research.

Risk may be linked to Vioxx's potency

The increased danger may stem from the fact that Vioxx contains much higher doses of certain COX-2 enzymes than Celebrex and some other medications in the class, suggests the study's lead author, Linda Levesque.

"The COX-2 inhibiting potency of rofecoxib is nearly 10 times greater than that of celecoxib or meloxicam, thereby possibly explaining the observed differences in risk," writes Levesque, a pharmacist and a PhD candidate in the school's department of epidemiology.

The McGill researchers used provincial databases tracking health-care insurance, prescriptions, hospitalization and other factors to follow 113,927 seniors newly prescribed with Vioxx, Celebrex or other drugs between Jan. 1, 1999 and June 30, 2002.

The Canadian Institutes of Health Research sponsored their research.

Concerns over COX-2 inhibitors

Celebrex, manufactured by Pfizer Inc., remains on the market despite recent concerns about it and other COX-2 inhibitors, commonly used to relieve pain and inflammation from arthritis.

There were renewed calls for its withdrawal this week, after Pfizer acknowledged Feb. 1 that a 1999 study indicated Alzheimer's patients taking Celebrex faced nearly four times the risk of cardiovascular problems than those taking a placebo.

While studies on the risks of Celebrex have produced mixed results, research into Vioxx has repeatedly linked it to heart problems and even deaths.

The U.S. Food and Drug Administration plans to meet mid-February to discuss the safety of all COX-2 inhibitors.