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Viagra May Treat Heart Failure
October 24, 2005
Viagra, famous for improving men's sexual function,
also appears to reduce the effects of hormonal stress on the heart
by 50 percent, claims a report by researchers at Johns Hopkins University.
Viagra (sildenafil) works
by helping genital blood vessels expand to maintain an erection,
but more recently, it has also been used as a treatment for pulmonary
hypertension. However, the drug has been thought to have no direct
effect on the heart." Unlike what was previously thought, drugs
like Viagra can in fact alter heart function," said lead researcher
Dr. David Kass, a professor of medicine at Johns Hopkins. "It
alters it particularly when the heart is stimulated by hormones.
"The report appears in the Oct. 24 online edition of Circulation.
Earlier research by Kass's team found that Viagra blocked the short-term
effects of hormonal stress in the hearts of mice. They also found
that, in mice, Viagra prevented and reversed the long-term cardiac
effects of chronic high blood pressure. In addition, Kass' group
found that, in mice, Viagra reversed the negative effects on heart
muscle weakened by heart failure and enlargement, a condition called
hypertrophy. In the current study, 35 healthy men and women with
no signs of heart disease received two separate injections of dobutamine
over three hours. Dobutamine increases heart rate and pumping strength.
Between injections, the patients were given Viagra or a placebo.
Then they all were given a second dobutamine injection. After the
first injection of dobutamine, the force of heart contraction increased
150 percent in all the patients.
However, in the group treated with Viagra, the increased heartbeat
was slowed by 50 percent." Viagra puts a brake on the effect
of dobutamine," Kass said. "It reduces the stimulation
of the heart so that the contraction of the heart was less strong."Kass
noted that his group is starting a clinical trial to see if Viagra
can be effective in patients with heart failure. "
If you gave a drug like Viagra not
just acutely, but chronically, you might be able to improve heart
function and reduce the chronic stress response in patients with
hypertrophy," he said. One expert believes that Viagra may
have a role to play in the treatment of heart failure. "This
research may lead to the development of a new use of the drug in
the treatment of diseases such as hypertension, hypertrophy and
heart failure, where beta-adrenergic activity is enhanced following
neurohormonal stimulation," said Rakesh C. Kukreja, a professor
of medicine, physiology, biochemistry and emergency medicine and
the Eric Lipman chair of cardiology at Virginia Commonwealth University
Medical Center. "These studies are complementary to the expanding
new role of Viagra and other relatively safe PDE-5A inhibitors as
powerful cardioprotectants," he added.However, another expert
was more cautious.
"It has a potential, but the crucial studies will be in actual
patients with cardiac conditions, and on other medications to see
if cardiac stress will be minimized with sildenafil," said
Hrayr S. Karagueuzian, a senior research scientist in the Division
of Cardiology at Cedars-Sinai Medical Center, in Los Angeles."
I am not going to buy it on its face value," Karagueuzian said.
"Let's see what happens. We simply do not know if the balance
of the sildenafil effect
will end up on the benefit or the deleterious side."
To read more, visit…
http://www.forbes.com/lifestyle/health/feeds/hscout/2005/10/24/hscout528707.html
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