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| Viagra started out life as a cardiovascular treatment — and some experts believe it should return to its root use. (Photo by William Vazquez/Pfizer/AP Photo) |
The little blue pill that has long been known to enable
and enhance sexual performance in men could also be used as a treatment for
heart disease, according to a new study.
Viagra hit the market in 1998 after the Food and Drug
Administration approved its use for the treatment of impotence in men. Over the
next decade, it became the most commercially successful drug on the market,
with more than 1.8 billion pills used by 35 million people.
Lost in Viagra’s salacious reputation was the fact that
the drug (under generic name Sildenafil) was originally designed to treat high
blood pressure and cardiovascular disease due to its ability to widen blood
vessels and increase blood flow. "Its results as an anti-angina drug were
only modest, but patients reported the unexpected side effect of improved
erections," explained lead author Andrea M. Isidori on the BioMed Central website. "The focus of
interest in this drug shifted rapidly from the heart to the bedroom."
Although Viagra was widely viewed as a successful
"love drug," its early history as a viable treatment for heart
patients was tainted when a some users suffered cardiovascular events, a few
resulting in sudden death. Afterward, most doctors stopped prescribing it to
men with heart disease. Later research found that the problems occurred when
Viagra was taken in combination with other medications containing nitro
compounds — used to regulate various aspects of the nervous, immune, and
cardiovascular systems. The drug combo increases the risk of a sudden drop
in blood pressure during sex, which could be harmful for someone with existing
heart problems. "Clearly, this is the result of a series of conditions
occurring simultaneously," said Isidori. "When Viagra is taken
correctly, it is no longer a concern."
The new study, which mainly focused on men, could not
only change the perception that Viagra is dangerous for people with heart
problems, but also show it can help improve
heart function. Phosphodiesterase-5 inhibitor (PDE5i) is the main ingredient in
Viagra and other drugs commonly used to treat erectile dysfunction. The
inhibitor blocks the enzyme PDE5, which prevents relaxation of smooth muscle
tissue. To test the effectiveness of PDE5i in safely protecting the heart, the
researches analyzed trials involving 1,622 patients who were treated with
either PDE5i or a placebo.
The research revealed that PDE5i prevented the heart from
enlarging and changing shape in patients suffering from left ventricular
hypertrophy, a condition that causes thickening of the muscles in the left
ventricle. PDE5i also improved heart performance in all patients with different
heart conditions, with no negative effect on the patients' blood pressure.
The study's authors concluded that PDE5i could be safely
administered to men who suffer from heart-muscle thickening and early-stage
heart failure. But because most of patients they analyzed were men, the
findings call for a larger trial on sex-specific, long-term responses.
"We found that the main ingredient in Viagra can be
used as an effective, safe treatment for several patients with heart
disease," Isidori said in a press statement. "Large clinical trials
are now urgently needed to build on these encouraging findings."
That is exactly what needs to happen, former president of
Pfizer Global Research and Development John LaMattinawrote on Forbes.com. But the kind of studies required
to further test PDE5i would take years and hundreds of millions of dollars to
conduct. LaMattina said he is skeptical that companies such as Pfizer
would be willing to take on such an expensive, long-term investment.
"Despite the interesting results, it remains to be seen whether a study of
sufficient size and robustness necessary for the regulatory approval of a PDE-5
inhibitor for use in heart failure patients will ever be done," he
concluded. "It is possible that an entity like the (National Institutes of
Health) would take this on. However, in this time of reining in healthcare
costs, the potential of PDE-5 inhibitors as drugs for treating heart failure
may never be realized."
By Ryan Wallace
Source: Yahoo
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