Canadians travelled "Viagra Highway" after drug's release delayed

CMAJ 1999;160:769

© 1999 Canadian Medical Association

The drug was initially expected to be available in Canada by late November. It has been sold in the US since April 1998, and it quickly became that country's best-selling prescription drug ever — 7 million prescriptions were written by mid-December. To date sildenafil has been approved for use in more than 50 countries.

Dr. Andre-Marie Leroux, medical officer at the Health Protection Branch, said the branch is examining cases of adverse drug reactions involving about 170 sildenafil-related deaths reported by the drug's manufacturer, Pfizer, by the end of August 1998. Most of these men had cardiac conditions and were using nitrate or nitrate derivatives. Advertisements and the drug's label clearly state that sildenafil should not be used by men who are taking nitrates in any form, including nitroglycerin.

Leroux said approval is also being delayed because of a shortage of staff in Health Canada's chemistry and manufacturing group, which is also reviewing sildenafil. Although he couldn't attach a precise number to the shortfall, he pointed out that Canada receives the same number of drug submissions as the US Food and Drug Administration but has a fraction of the staff. "The FDA has 8 times as many people," he said.

Another reason for the delay is that sildenafil was considered a priority drug in the US, but in Canada the high priority is assigned to drugs used to treat cancer, AIDS and other life-threatening diseases.

"People are frustrated when drugs are approved in the US but not available in Canada, but certain drugs just go through later," Leroux explained. A road connecting Canada with upper New York State has already been dubbed the "Viagra Highway" because of the number of Canadians crossing the border to buy the drug.

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