Viagra appears to be an effective treatment for pulmonary arterial hypertension or PAH

Clinical studies have demonstrated that Viagra appears to block the action of PDE5A, an enzyme which helps break down a molecule known as cyclic GMP, thereby prolonging the vasodilatory effect of nitric oxide.

This molecule helps the heart resist hormonal stresses and enlargement of the heart by 50 percent.

PAH is characterized by dangerously high pressure in the blood vessels that lead from the heart to the lungs.

It is estimated that about 100,000 people worldwide are afflicted with PAH. Symptoms include difficulty breathing, dizziness and fatigue.

Left untreated, patients have an average survival time of less than three years from the time of diagnosis. In the pivotal Viagra trial, patients taking 20 mg three times daily, which became the FDA-approved dose, increased six-minute walk distances by 45 meters, which was significantly better than patients in the placebo group.

At the end of one year, walking distances and functional class remained stable and 94 percent of patients were still alive.Though Tracleer (bosentan) was the first oral medication to be approved for PAH, costing about $40,000 a year, Viagra is expected to cost considerably less for patients.

Interestingly, unwanted erections did not pose a problem with those study patients taking Viagra most patients were female, and no males reported complaints.

Though Viagra continues to have a hold in the erectile dysfunction market, patients afflicted with debilitating cardiovascular and pulmonary diseases such as PAH, can begin to reap the benefits from this drug's potentially lifesaving qualities.

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