Four per cent of new drugs approved by the Canadian government between 1990 and 2010 were eventually pulled off the market for safety reasons, according to a new study. And it took up to three-and-a-half years for half of the drugs to be withdrawn.
“This really points to a serious problem,” says Joel Lexchin, an emergency physician, professor of health policy of York University in Ontario and author of the study.
First years “really dangerous”
“When drugs are initially marketed we actually have very little information about their safety. That’s because they’ve typically been tested on small groups of people that don’t represent the wide range that are going to use the drug once it’s available for doctors to prescribe.
“So, within the first three-and-a-half years or so, that’s the really dangerous part. That’s when we’re finding out new safety problems about drugs and they really should be used very cautiously during that period of time,” says Lexchin.
Health Canada “not transparent”
Some drugs were approved with a warning and then soon after were withdrawn altogether. Lexchin says not enough information is given by the government department, Health Canada so doctors and consumers can understand the process and the dangers of specific drugs.
A wide range of medicines were studied including those marketed to treat cancer, high blood pressure, obesity and neurological disorders. They were often pulled for their negative effects on the cardiovascular system or liver. Sometimes they were fatal.
“Use extreme caution”
“In the first three or four years when a drug is marketed my advice is that unless there’s nothing else available for this problem, or unless this drug is substantially better than anything else that’s on the market, that doctors prescribe any new drug with extreme caution and that patients similarly should be very cautious,” says Lexchin. It’s advice that he himself follows in his own practice of medicine.
The study was published in the journal Open Medicine.
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