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Just one year after it was approved for use in Canada, federal health officials are investigating safety concerns about smoking cessation prescription drug Champix amid fears it is linked to suicide and serious psychological problems.

The investigation and reports of major side effects highlight what many medical experts describe as chronic problems with the way new drugs are approved in Canada and the ability of government officials to adequately monitor them once they're put on the market.

"Existing systems don't really seem to be adequate," said David Henry, chief executive officer of the Institute for Clinical Evaluative Sciences in Toronto. "That means often times the studies that are the basis for market approval are not large enough to test for safety properly."

The U.S. Food and Drug Administration issued a safety warning Friday.

The warning was to alert the public to reports of suicide, depression and changes in behaviour that may be linked to the drug. Pfizer manufactures the pill, which has been available in the United States since May, 2006, and is sold there under the name Chantix.

The FDA said, "it appears increasingly likely that there may be an association between Chantix and serious neuropsychiatric symptoms," and is urging doctors to take the reports of health problems into serious consideration before issuing a prescription for the drug.

Canadian drug stores purchased $17.6-million worth of Champix since its introduction to the market one year ago, according to IMS Health Canada, a private company that tracks prescription drug sales.

Unlike many smoking cessation aids, Champix doesn't contain nicotine. Rather, it's a drug that targets nicotine receptors in the brain to reduce cigarette cravings. Champix was touted by Pfizer, as well as prominent advocacy groups and physicians, as a major breakthrough in the battle against smoking when it was approved by Health Canada at the end of January, 2007.

But months after it approved the sale of Champix, Health Canada launched an investigation into reports of serious psychological problems in those taking it to determine whether it presents a public health risk.

The investigation has been continuing for at least a month, and the public will be alerted if there are serious concerns associated with the product, according to Health Canada spokesman Paul Duchesne.

But concerns with Champix have already prompted Health Canada and Pfizer to quietly update the product label to warn doctors and patients about the possibility of serious psychological side effects.

Pfizer Canada said in a statement that the label, updated in December, includes "spontaneous postmarketing adverse event reports of depressed mood, agitation, changes in behaviour, suicidal ideation and suicide in patients attempting to quit smoking while taking Champix."

The company said there is no conclusive link between health problems and the drug, and that people who try to quit smoking have been found to suffer from underlying psychiatric problems. Side effects in clinical trials of more than 5,000 patients were rare, while tobacco kills thousands of Canadians every year, the company's statement said.

However, some experts point to Champix as an example of the risks often associated with new drugs and the lack of information given to consumers.

"Part of the problem is that when a person is considering whether to use a prescription drug ... often they don't have the key information they need to know," said Barbara Mintzes, a professor in the department of anesthesiology, pharmacology and therapeutics at the University of British Columbia who studies drug safety and clinical evidence.

One of the major issues that prevents consumers from getting critical information is that clinical data used by Health Canada to assess drugs is kept secret, she said. The process should be made more transparent and companies should have to prove their new product offers a unique benefit over existing treatment in order to be approved, she added.

Dr. Henry of ICES in Toronto said Health Canada is also under pressure from drug companies looking to boost profits to grant drug approvals quickly, even if the drug may not offer a unique advantage.

"What we're seeing are companies that are struggling to find footholds in very competitive mass markets where generics are appearing," he said.

People using Champix are looking for an aid that can help them quit smoking, but those concerned about potential problems may find more success using alternatives, Dr. Mintzes said.

"Most people can quit smoking without pharmaceuticals," she said.