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 at 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.
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 [nonarteritic anterior ischemic optic
neuropathy]," Gerald McGwin, who headed the
study, wrote in a report in the British Journal of
Ophthalmology. NAION is the most common cause of acute
optic nerve disease in people over 50 years of age. It can
cause permanent loss of vision in one or both eyes.
McGwin and his
team questioned 76 men, half of whom suffered from NAION,
who were being treated at a specialist eye clinic in
the United States about their smoking and drinking
habits and use of anti-impotence pills.
Viagra, made by
Pfizer, and Eli Lilly's Cialis are leading impotence
treatments. Tens of millions of men have used Viagra and
Cialis since the treatments were introduced.
Some studies have
shown that gay and bisexual men are more likely to have
tried or to regularly use erectile dysfunction drugs. The
impotence drugs also are popular among users of club
drugs like ecstasy and crystal methamphetamine to
counter the erection-inhibiting effects of these drugs
and allow the users to engage in sex, often with multiple
partners, according to researchers.
In May, the U.S.
Food and Drug Administration said it had received more
than 40 reports of NAION involving impotence drugs but had
not determined whether the treatments were
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 of
NAION. "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.
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 says. (Reuters, with additional
reporting by Advocate.com)