Many of the pharmaceutical drugs taken by Canadians, from Aspirin to cholesterol-lowering pills, are manufactured overseas in countries such as China and India where the safety record of plant inspections is uncertain, a drug policy expert says.

Health Canada regularly emails foreign product alerts about non-prescription products for erectile dysfunction with names like Uprizing 2.0 that may contain the drug sildenafil — prescribed to treat impotence.

How often do North American regulators check overseas pharmaceutical manufactuers? (Jacques Boissinot/Canadian Press)

The alerts made drug policy researcher Alan Cassels of the University of Victoria question if prescription drugs manufactured overseas are safe and who regulates them.

About three-quarters of drugs imported to Canada are sourced from countries that Canada doesn't have standing agreements with about drug manufacturing standards, including the U.S., Stephanie Reid, a manager at Health Canada’s drug inspection unit, said in an interview with CBC News.

"Canadians can be assured that before any product comes into the country, there's always an inspection," Reid said.

The inspections can be by trusted partners such as the U.S., Europe or Australia or by Health Canada itself, she added.

Most of the North American supply of Aspirin comes from China, which produces about 120 billion tablets a year, Cassels said. Other widely used drugs, such as omeprazole, used to reduce gastric acid secretions, and cholesterol-lowering simvastatin, often come from Puerto Rico and China.

"How often do our regulators dust off their passports and fly to China or India to ensure that the plants producing pharmaceuticals are clean, follow proper manufacturing techniques and contain what is on the label [and nothing else]?" Cassels wrote in an editorial in Monday's issue of the Canadian Medical Association Journal.

Heparin contamination fallout

In 2008, contaminated heparin, used to prevent and treat blood clots, was tied to dozens of adverse reactions, including deaths, in the U.S.

The cases fuelled calls for the U.S. Food and Drug Administration to increase its oversight of overseas manufacturing and improve its tracking systems, the Pew Health Group said in its report titled "After Heparin."

From Jan. 1, 2008, to April 4, 2008, Health Canada said it received 14 adverse reaction reports suspected of being associated with heparin. Two were described as allergic reactions and none were fatal, the department said in an email.

When Cassels emailed Health Canada, he was told that the department conducted 35 inspections at foreign sites in the last five years.

Cassels's questions to Health Canada about how the inspections work, how often plants fail and how often imports were stopped because of substandard manufacturing weren't answered. Health Canada said the information is proprietary and only shared with the companies and regulatory partners.

"We see recalls do happen," Reid said. "But then actions are taken to correct those issues."

Russell Williams, president of Canada's Research-based Pharmaceutical Companies (Rx&D), said its member companies are dedicated to ensuring the safety and quality of medicines and vaccines.

"Good manufacturing processes are not simply a guideline in Canada; they are the law under the Food and Drugs Act," Williams said in a statement.

"In order to fabricate, package, label, distribute, import, wholesale or test a drug for use in Canada, a Drug Establishment Licence is required. Any facility — foreign or domestic — that performs of these tasks for a manufacturer or importer must be approved by Health Canada."

With files from CBC's Kelly Crowe and Pauline Dakin