January 16, 2006

Impotence drugs linked to eye damage risk -study

By Patricia Reaney

LONDON (Reuters) - Impotence drugs such as Viagra and
Cialis can increase the risk of eye damage in men who have a
history of heart disease or high blood pressure, researchers
said on Tuesday.

In a small study, scientists at the University of Alabama
in Birmingham found that men who had suffered a heart attack
were 10 times more likely to have optic nerve damage if they
had been taking leading anti-impotence pills.

"For patients with a history of myocardial infarction
(heart attack), we did observe a strong and statistically
significant association suggestive of a link between the use of
Viagra and/or Cialis and an increased risk of NAION," Dr Gerald
McGwin, who headed the study, said in a report in the British
Journal of Ophthalmology.

Non-arteritic anterior ischaemic optic neuropathy (NAION),
is the most common cause of acute optic nerve disease in people
over 50 years old. It can cause permanent loss of vision in one
or both eyes.

Viagra, made by Pfizer Inc and Eli Lilly and Co's Cialis,
are leading impotence treatments.

McGwin and his team questioned 76 men, half of whom
suffered from NAION, who were treated at a specialist eye
clinic in the United States, about their smoking and drinking
habits and use of anti-impotence pills.

The researchers found that men who had had a heart attack
were 10 times more likely to have optic nerve damage if they
had taken the anti-impotence drugs.

Tens of millions of men have used Viagra and Cialis since
the treatments were launched.

In May, the Food and Drug Administration (FDA) in the
United States said it had received more than 40 reports of
NAION involving impotence drugs but had not determined whether
the treatments were responsible.

Pfizer said a review of 103 Viagra clinical trials
involving more than 13,000 patients found no reports of NAION.
But the company has changed the label on Viagra to note reports


"The labels have been updated," said a spokesman.

Eli Lilly has also changed its labels on Cialis. No one
from the company was immediately available to comment on the
new research.

McGwin and his team said patients with heart disease or
high blood pressure should be warned about the elevated risk of
NAION when taking anti-impotence pills.

"Though NAION is a rare condition, the large number of men
using Viagra or Cialis suggests that, should an association
truly exist, the incidence of NAION could rise dramatically,"
McGwin added.