(Philadelphia, PA) – Researchers at the
University of Pennsylvania School of Medicine say
preliminary results of a small study show promise in improving erectile
dysfunction (ED) in men who had shown minimal reaction to Viagra.
The study results are published in the March issue of the Journal
of Sexual Medicine.
Erectile dysfunction is often a sign of a more severe vascular
problem that involves abnormalities in the lining of the blood vessels.
And often, endothelial dysfunction is an underlying problem for
ED – it can be one of the first signs of atherosclerosis,
a build-up of plaque and blockages in the arteries.
“It’s already known that there is a connection between
erectile dysfunction and coronary disease. The risk factors are
the same for both, and thus, ED can be a marker for coronary disease,”
explains lead author Howard Herrmann, MD, Professor
of Medicine and Director of the Interventional Cardiology and Cardiac
Catheterization Laboratories at the Hospital of the University
of Pennsylvania. “Normal erections are caused when
nitric oxide is made, but with endothelial dysfunction, the body
doesn’t make enough of it, causing the erectile dysfunction.
Normally, Viagra prevents the breakdown of the little nitric oxide
that is there, so that there is enough of it for an erection to
However, about 10-30 % of men are classified as “Viagra non-responders”
– in these men, Viagra did not significantly help their erectile
dysfunction. So in a small, double blind, randomized, placebo-controlled
study at Penn, Herrmann looked at a dozen patients with ED who had
not responded well to Viagra. He gave them either a high-dose Lipitor
or a placebo. He then rechallenged them with Viagra and asked if
the ED had improved.
“There did seem to be some improvement for those who received
Lipitor versus the placebo,” said Herrmann. “We theorized
that if you could make the edothelium healthier through the use
of statins -- so that there is more nitric oxide available -- you
would improve the endothelial dysfunction and Viagra would work
better for the patient.”
And there are other potential benefits too. Stan Schwartz,
MD, Director of the Diabetes Disease Management program
at Penn and co-author, states, “Patients with Diabetes, both
Type 1 and Type 2, are plagued with complications of the diabetic
state that involve endothelial dysfunction. This research points
us in a direction that says any drug class that improves endothelial
dysfunction may also be beneficial to patients with diabetes.”
Additionally, Emile Mohler, MD, Director of Vascular
Medicine at Penn and co-author, cautions, “ED is a sign that
cholesterol plaque may be present in the heart, neck or leg arteries.
Men with ED should be evaluated for vascular disease.”
“These preliminary results show promise,” adds Herrmann.
“They support the hypothesis that erectile dysfunction may
be one sign of a generalized vascular disorder characterized by
endothelial dysfunction and that statin drugs may improve the endothelial
dysfunction, even before altering the lipid profile. But the results
are preliminary and warrant further testing in a larger clinical
trial,” he cautions.
It should be noted that beyond endothelial dysfunction, there are
other reasons Viagra may not work well for someone.
The results of this study were published in the March 2006 issue
of the Journal of Sexual Medicine. Members can access the
journal on-line at: http://jsm.issir.org/. The article is titled,
“Can Atorvastatin Improve the Response to Sildenafil in Men
with Erectile Dysfunction Not Initially Responsive to Sildenafil?
Hypothesis and Pilot Trial Results.”
This study was supported by an unrestricted medical center grant
Editor’s Note: Dr. Howard Herrmann has received
honorarium from Pfizer and Lilly ICOS. Dr. Stan Schwartz is a consultant
and has received a speaker’s honoraria from Lilly ICOS. Dr.
Emile Mohler is part of the speaker’s bureau for Pfizer.
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