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ALL
CLEAR FOR VIAGRA
Erectile dysfunction, which affects up to 30 million men in the
United States, may be particularly common in patients with heart
disease because of the presence of overlapping risk factors --
including age, diabetes, hypertension, hypercholesterolemia, and
smoking. Following the approval by the Food and Drug Administration
of oral sildenafil (Viagra) for the treatment of erectile dysfunction,
a number of serious cardiovascular events -- including heart attack
and sudden cardiac death -- were noted associated with the use
of the drug. Consequently, physicians and patients have remained
uncertain about whether these reported events were related directly
(and solely) to the use of Viagra or to the patient's underlying
cardiovascular disease ... or, perhaps, some combination of these
and other factors, including the physical exertion of sexual activity.
To determine what adverse cardiovascular effects,
if any, Viagra might produce in men with heart disease, Penn
researchers identified
and measured a number of systemic, pulmonary and coronary function
variables -- including heart rate, blood pressure and coronary
blood flow -- both before and after the oral administration of
the drug in 14 male patients. "We found that Viagra had no
direct adverse cardiovascular effects in men with severe cornary
artery disease," said Howard C. Herrmann, MD, Professor of
Medicine at the University of Pennsylvania Medical Center and lead
author of the study, which appears in the June 1 issue of the New
England Journal of Medicine. "In addition, we noted a small
beneficial effect on coronary blood flow reserve.
"Our data support the consensus position of the American
College of Cardiology and the American Heart Association that sildenafil
is safe for patients with stable coronary artery disease who are
not taking medications containing nitrates, " adds Dr. Herrmann.
All study participants had severe stenosis (or narrowing) of at
least one coronary artery and had been referred to the Hospital
of the University of Pennsylvania (in Philadelphia) for angioplasty.
Among these men -- whose mean age was 61 years -- there were high
rates of hypertension (57%), diabetes (43%), and smoking (57%).
All patients had stable symptoms that permitted the discontinuation
of nitrates at least 24 hours prior to the ingestion of Viagra.
Other prescribed medications -- including beta-blockers, aspirin,
heparin, and vessel-dilating drugs -- were continued.
To obtain base-line data, researchers measured systemic, pulmonary
and coronary blood pressures and flows in patients prior to the
ingestion of Viagra while they were undergoing cardiac catheterization.
Then, one hour after drug intake, the same measurements were repeated.
The research team found small, but significant, decreases in arterial
blood pressure and pulmonary pressure; and noted no significant
changes in coronary artery diameter and blood flow, or coronary
vascular resistance. Overall, they found no adverse effects attributable
to Viagra; and no patient had angina or any other side effect that
could be attributed to sildenafil.
Dr. Herrmann cautions that, while his study shows that Viagra
has no measurable negative effect on the circulation of blood in
men with severe coronary disease, it does not address the possibility
that severe cardiac events may be caused in some patients by an
interaction with other drugs (particularly nitrates) or by the
combination of Viagra use with sexual activity -- which increases
heart oxygen demand.
The study also does not address the risks of either
Viagra or sexual activity in patients with unstable angina, recent
heart
attack, or congestive heart failure. "This study does, however,
show that Viagra itself if a safe drug that could benefit many
patients who have both erectile dysfunction and coronary artery
disease," adds Dr. Herrmann.
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