A study, published in the New England Journal of Medicine ( NEJM ) showed Revatio ( Sildenafil citrate ) to be effective in treating the symptoms of pulmonary arterial hypertension ( PAH ) in adults.

Sildenafil citrate is the same active ingredient found in Viagra.

The 20 mg dose of Revatio was approved by regulatory authorities in the United States and Europe for the treatment of pulmonary arterial hypertension in adults.

Pulmonary arterial hypertension is a rare and fatal disorder characterized by dangerously high pressure in the blood vessels that lead from the heart to the lungs. The symptoms of PAH include fatigue, breathlessness and dizziness, which often reduces or prevents normal daily activities for patients.
Pulmonary arterial hypertension is estimated to affect approximately 100,000 people worldwide, and is more likely to affect women between the ages of 20 and 40.

The double-blind, placebo-controlled study of 278 patients with symptomatic pulmonary arterial hypertension showed Revatio significantly improved exercise capacity, hemodynamics and functional classification.
Patients in the study received 20, 40, or 80 mg of Sildenafil three times daily or placebo.
Similar efficacy was observed for each dose.

" These results demonstrate the efficacy and safety of Sildenafil in treating patients with symptomatic pulmonary arterial hypertension," said lead study author, Nazzareno Galiè of the Institute of Cardiology, at the University of Bologna, Italy. " I believe that the novel mechanism of action and the risk-benefit profile of Sildenafil may provide a favorable treatment option for patients with pulmonary arterial hypertension."

The 12-week study assessed improvement in exercise capacity as measured by a six-minute walk test, the standard measure of efficacy in pulmonary arterial hypertension trials. Patients taking Revatio showed a 45- to 50-meter improvement in walk distance. Additionally, patients had improvements in cardiopulmonary measurements including pulmonary artery pressure, pulmonary vascular resistance and cardiac index.

Patients on all doses of Revatio showed improvement in the severity of their disease ( functional class ). Of those patients taking 20, 40 and 80 mg dose of Revatio, 28, 36 and 42 percent, respectively, showed improvement in the severity of their disease compared with seven percent of patients taking placebo.

At the end of a one year, open-label extension study, 95 percent of patients were still alive. Patients also maintained their improvement in the six-minute walk distance at one year ( 51-meter improvement, compared with a 48-meter gain at week 12 ). Without a control group, these data must be interpreted cautiously.

All Revatio doses were well tolerated. The most common side effects were nose bleeds, headache, dyspepsia, flushing, and insomnia, which were characterized as mild to moderate.

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 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.

Source: Pfizer, 2005


XagenaMedicine2005