FDA ( Food and Drug Administration ) approved Revatio ( Sildenafil ) as a treatment for pulmonary arterial hypertension ( PAH ), a rare, aggressive and life-shortening vascular disease.
Sildenafil is the active ingredient in Viagra, Pfizer's erectile dysfunction medication.

PAH is characterized by dangerously high pressure in the blood vessels that lead from the heart to the lungs.
It is estimated to affect approximately 100,000 people worldwide. 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.

The FDA granted Revatio a priority review. The FDA approval was based on results of a large randomized, double-blind, placebo-controlled study involving 277 patients with PAH.

The study measured the exercise capability of patients after 12 weeks of treatment.
Patients were randomized to receive Revatio 20 mg, 40 mg, or 80 mg three times a day or placebo.
All three treatment groups showed highly significant improvements in the six-minute walk distance, the standard measure of efficacy in PAH trials, compared to patients who received placebo. No differences were observed among the Revatio doses studied -- therefore, the approved dosage is limited to 20 mg three times daily.

Patients taking Revatio also showed improvements in mean pulmonary artery pressure and other measures of cardiac function. A long-term non-placebo controlled extension trial was also conducted. At the end of one year, walk distance and functional class were stable and 94 percent of patients were still alive.

Revatio is the first oral treatment for pulmonary arterial hypertension to be approved for patients with an early stage of the disease, allowing physicians to treat patients earlier in this progressive disorder.

Revatio was generally well tolerated at all doses studied. The most common side effects were headache, dyspepsia, flushing, epistaxis, and insomnia.

The Revatio 20 mg pill is white and round to distinguish it from Viagra's blue diamond-shaped pill for erectile dysfunction.

Revatio is indicated for the treatment of pulmonary arterial hypertension to improve exercise ability. The efficacy of Revatio has not been evaluated in patients currently on Bosentan therapy.

The use of Revatio or Viagra and organic nitrates in any form, at any time, is contraindicated. Side effects were similar to the established safety profile of Viagra used for the treatment of erectile dysfunction.

The most common side effects of Viagra are headache, facial flushing and upset stomach. Less commonly, bluish vision, blurred vision or sensitivity to light may briefly occur.

Source: Pfizer, 2005


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