Because of the rising costs of brand-name drugs, more and more Canadians are looking for generic medicines to fill their prescriptions at the pharmacy. But according to health experts, that decision could come with serious complications.
While generic drugs have the same active ingredients as their branded equivalents, those active ingredients behave in similar, but not necessarily identical, ways in the body. In addition, the non-active ingredients in generic drugs could differ from those found in their pricier counterparts. Those differences could affect the way generic drugs work as compared to the reference pharmaceutical.
“[W]hat you want to reach is a certain level in the blood that is considered to be sufficient in order for the drug to achieve its goal in terms of efficacy but not necessarily to exceed it,” Brian White-Guay, a former professor in the Faculty of Pharmacy at the Université de Montréal, told Global News. “[I]f you go over a certain level of exposure, you might have undesirable side effects.”
According to David Price, professor and chairperson of the Department of Family Medicine at McMaster University, there are specific instances where people who’ve been on a proprietary drug are better off sticking to it. Psychotropic drugs, such as antidepressants and anti-psychotics, are notable examples.
“The assumption has been that if [a generic drug’s] pharmacological structure is similar, then [its] safety, efficacy and tolerability is also similar,” said professor of psychiatry and pharmacology Roger McIntyre from the University of Toronto. But he told Global News that he’s seen at least 10 cases where patients who were stable for years on anti-depressants relapsed after their pharmacy started filling their prescriptions with generic drugs.
White-Guay said even switching between generic drugs, which are similar but not identical to one another, could be problematic. A difference in non-active ingredients could cause side effects in some patients or affect the way an active drug behaves in the body, he explained.
Concerns from switching to different unbranded drugs are growing as patents on blockbuster drugs expire, opening the gates for generic manufacturers. Public and private health insurers — under pressure from increasing prescription-drug use, aging populations, and astronomical prices of breakthrough drugs — are also trying to contain costs via a push toward more generic drug use.
Shortages in some brand-name or generic drugs could also force some Canadian patients into other generic substitutes, according to a recent CD Howe study co-written by White-Guay. He said doctors may indicate “do not substitute” on a drug prescription if necessary, but patients are often unable to tell when they’ve gone from a brand-name to a generic, or switched between generics.
Price said switching between versions of the same drug rarely creates issues, but the risk is increased for those who try mail-order drugs, which may not meet Health Canada’s standards.
“Often, you pay for what you’re getting,” he said.
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