LOS ANGELES, March 12 (UPI) -- The erectile-dysfunction drug Viagra appears to help the exercise capacity of patients with pulmonary fibrosis, say U.S. researchers.
Idiopathic pulmonary fibrosis is an incurable disease marked by progressive scarring in the lungs, which often necessitates a lung transplant, but the disease can also cause pulmonary hypertension, which lessens blood flow to the lungs, making breathing -- and thus, exercise -- more difficult.
But researchers at the University of California at Los Angeles say pulmonary-fibrosis patients taking Pfizer's Viagra were able to improve their walking function, upping 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, David Zisman, medical director of UCLA's Interstitial Lung Disease Program.
In the pilot study, 14 patients with the disease initially took a standard six-minute walking test, then were given Viagra for three months. The patients then took 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, with an average improvement in distance of 161 feet.
Eleven patients completed the study, and two of that group stopped the medication due to side effects.
The study is published in the March issue of the journal Chest.
