The evolution of magic blue

Viagra has evolved from a drug for treating hypertension to a treatment for heart attacks. In 1998, the US Food and Drug Administration approved a new drug for treating male erectile dysfunction, Viagra®, scientifically known as sildenafil citrate. But Viagra began its life as a potential treatment for hypertension, and then angina. When a 10-day high dose study turned up an unusual side effect, Viagra suddenly became a household word. The blue pill provided millions of frustrated men with an alternative to available treatments – injections, implants, and pumps. Unlike other therapies, Viagra has no effect in producing erections in the absence of sexual stimulation.

On March 2, Virginia Commonwealth University researchers reported another positive effect of the little blue pill. Viagra, and Levitra®, generically known as vardenafil, may be better than nitroglycerin in protecting the heart from damage before and after a severe heart attack.

Rakesh C. Kukreja, Ph.D., professor of medicine and Eric Lipman Chair of Cardiology at VCU, and colleagues compared nitroglycerin with two erectile dysfunction drugs – Viagra and Levitra — to determine the effectiveness of each for heart protection following a heart attack. Nitroglycerin is a drug used to treat angina, or chest pain. It is a vasodilator and opens blood vessels in order to improve the flow of blood to a patient’s heart.

The research team reported that in an animal model, sildenafil and vardenafil reduce damage in the heart muscle when given after a severe heart attack. In contrast, nitroglycerin failed to reduce the damage in the heart when administered under similar conditions. Read entire story.

It is important to note that the research team’s report was on an animal model, not humans, although the report does seem promising. On the other hand, Viagra is approved to treat erectile dysfunction, so should it be used by men with heart disease? Men who already have heart disease can risk further heart damage when they have sex. In 2004 the government ordered Pfizer Inc. to pull television ads that promised better sex for men taking Viagra because the TV ads failed to inform viewers of known risks associated with the drug.

Viagra has two actions that may be of consequence in patients with heart disease. First, it can lower the blood pressure. Second, it interacts with nitrates.

Viagra is a vasodilator, and consequently it lowers the systolic blood pressure (the “top” number in blood pressure measurements). In the majority of patients with heart disease, including most of those being treated with antihypertensive drugs, this is not a problem. Patients taking drugs that contain nitrates have been warned not to take Viagra because of sudden, unsafe drops in blood pressure.

The American College of Cardiology and the American Heart Association concur that Viagra is safe for men with stable coronary artery disease who are not taking nitrates, but should never be used in patients who are taking nitrates. There are other groups of heart patients for whom Viagra may be potentially dangerous. These include patients with heart failure accompanied by borderline low blood pressure, some patients with hypertrophic cardiomyopathy, and possibly, patients on complicated drug regimens for hypertension.

So is Viagra a safe treatment to prevent and reduce damage to the heart muscle? And what new uses for magic blue may we expect in the future?

Information for this blog entry was modified from:
http://www.news.vcu.edu/news.aspx?v=detail&nid=1967
http://www.msnbc.msn.com/id/6495250/
http://heartdisease.about.com/cs/coronarydisease/a/viagraheart.htm
http://www.chemsoc.org/chembytes/ezine/1999/viagra.htm
http://pubs.acs.org/hotartcl/mdd/98/novdec/viagra.html

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