researchers have found that Viagra may help patients with idiopathic pulmonary fibrosis, an incurable disease characterized by progressive scarring in the lungs, which often leads to a lung transplant.

Published in the March issue of the journal Chest, the research shows that more than half of the patients treated with Viagra, also known medically as Sildenafil, improved their walking distance by at least 20 percent during a standard test to measure lung function.

"Over five million worldwide suffer from this devastating disease, so we are hopeful that this drug may prove an effective therapy for pulmonary fibrosis," said the study's principal investigator, Dr. David A. Zisman, medical director of UCLA's Interstitial Lung Disease Program and assistant professor of pulmonary and critical care medicine at the David Geffen School of Medicine at UCLA.

Many patients with pulmonary fibrosis also have pulmonary hypertension, which constricts arteries and lessens blood flow to the lungs, resulting in diminished lung capacity and breathing difficulties. According to Zisman, Sildenafil may help breathing by opening or dilating blood vessels to allow more blood flow to the lungs.

In this pilot study, 14 idiopathic pulmonary fibrosis patients initially took a standard six-minute walking test. All patients were then given oral Sildenafil therapy for three months, followed by a second walking test to gauge performance changes.

Researchers noted that 57 percent of the patients improved their walking distance by 20 percent or more. The average improvement in walking distance was 49 meters (161 feet).

Eleven patients completed the study. Only two patients experienced side effects and had to stop the medication - one due to diarrhea and the other due to abnormally low blood pressure.

"In this small pilot study, the drug was well-tolerated," said Zisman. "The next step is to confirm this finding in a large, randomized clinical trial."

The study was funded by the National Institutes of Health.