Canadian Drug Surveillance: A Sick System?

Pop a pill. Cure your headache….Damage your liver? In recent years, critics have pointed fingers at Canada's drug monitoring system, claiming that inefficiencies in how drugs are tracked after approval contribute to needless injuries and deaths. More steps, they argue, are needed to safeguard the public from pharmaceuticals that linger on the market even after evidence suggests there may be cause for concern.

Health Canada's Therapeutic Products Directorate (TPD) is responsible for approving and monitoring drugs. Once a product is approved based on an analysis of data provided by the manufacturer, it receives an identification number and marketing begins. Prescriptions are filled to the tune of $12.3 billion in 2001, according to the Canadian Institute for Health Information.

When a patient experiences an adverse drug reaction, it may be reported to the TPD or drug manufacturer. Last year, 8,566 adverse reaction (AR) forms were filed up 15 percent from 2001 at 7,389. The system has seen small increases for the past five years, but adverse reaction reports remain voluntary. As a result, current AR figures are believed to be about one-tenth of the total number. An extrapolation of one well-publicized 1998 University of Toronto study looking at US data suggests that up to 10,000 Canadians die from not just experience adverse drug reactions each year.

This lack of systematic collection makes it more difficult to identify problematic drugs. We saw it in 2000 with the cardiac drug Prepulsid (cisapride), which was earmarked first in the US but wasn't pulled off the shelves until more than seven million Canadian prescriptions had been written. Part of the challenge was that we didn't have enough national data, according to Dr. Michelle Brille-Edwards, senior physician responsible for drug approval in Canada from 1988 to 1992, in a phone interview from Ottawa. Ironically, "We had info from the World Health Organization on cisapride as early as 1992," she says. Still, it wasn't until years later that anything was done.

So what is being done now? When they do occur, drug warnings are routinely printed in newsletters and the Canadian Medical Association Journal, where they may be seen by professionals but less often by the public. Last year, the TPD was re-formed as part of the government's publicized attempt to combat this admittedly complicated problem.

"It's no different than it was before," says Dr. Brille-Edwards. "There's no evidence that [the] operates any differently than it did a year ago." An inquest into the death of a teenager after taking Prepulsid generated numerous recommendations for strengthening the drug safety system. It's unclear which recommendations if any are being acted upon.

The proof of the TPD's change in status may very well lie in how efficiently it reacts to possible threats to public health. There is currently another drug in the media's eye: Eprex. Prescribed in Canada since 1990 to treat anemia among kidney dialysis patients, it has been linked to a serious blood disorder called pure red cell aplasia (PRCA). Worldwide, 141 cases of PCRA have been reported, 37 in Canada. Other countries have pulled Eprex off the shelves. But not us. A Health Canada spokesperson stated in July 2002 that patients shouldn't stop taking Eprex without doctor consultation.

In the meantime, the prescription drug portion of health-care spending has more than doubled since 1985. The average Canadian now spends about $500 annually on drugs. If you are concerned about an adverse reaction, anyone can make a report by contacting Health Canada at 1-866-234-2345. E-mail cadrmp@hs-sc.gc.ca.

Adverse Reaction Reports Received by Health