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Canada issues warning on Viagra vision loss

Posted on: Tuesday, 26 July 2005, 15:48 CDT

TORONTO (Reuters) - Canada advised users of the erectile dysfunction drugs Viagra, Cialis or Levitra on Tuesday to seek "immediate medical attention" if they experience sudden vision loss or other vision problems when taking the drugs.

Health Canada, the federal health ministry, also said in a statement it was likely to change the product information for the three popular drugs.

Earlier this month the U.S. Food and Drug Administration approved new labeling to warn men about possible blindness from Pfizer Inc.'s Viagra.

The U.S. warning labels also affect Cialis, sold by Eli Lilly & Co. and Icos Corp., and Levitra, which is co-promoted by GlaxoSmithKline and Bayer AG .

"Health Canada is advising individuals who use the drugs Viagra, Cialis and Levitra to consult their physicians and seek immediate medical attention if they experience sudden vision loss or vision-related problems while taking these drugs," the statement said.

Later, Health Canada's spokeswoman, Nathalie Lalonde, said it was too early to say whether the agency's decision would be similar to the FDA's.

"We anticipate that we will be in a position to make a decision in terms of labeling changes within the next two to three months," she said.

The ministry said it was reviewing two Canadian reports of Viagra users who suffered a specific type of vision loss -- known as non-arteritic anterior ischemic optic neuropathy -- which has been linked to impotence drugs.

Health Canada said it did not know if the vision problems outlined in the two reports were linked to the drugs.

The statement cited a March article in the Journal of Neuro-Ophthalmology on 14 cases of Viagra users suffering the rare eye condition, in which the blood supply to the optic nerve where it enters the eye is interrupted. All the cases involved other risk factors for the condition, including high blood pressure.

"The March paper did send us a signal, raised an antenna," said Lalonde.

"We don't make our decision based on such information. However it does bring it forward as something that needs to be looked into a little bit further and that's what we are doing at this point."

Health Canada said it has asked for more safety information from the drug firms.

A spokeswoman for Pfizer said the company was "committed to working with Health Canada to determine what label change needs to be made with respect to serious eye conditions."

Likewise, Bayer and Eli Lilly said they were working with Health Canada and would make changes to their labels upon request.

Source: REUTERS

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