Researchers from University of Texas observed that Viagra could be used to treat heart and lung disease. The reports are accurate, but based on a small experiment in healthy young men, the results of which do not translate directly to people with chronic heart and lung disease.
They report that the drug may be useful in treating people with pulmonary hypertension (caused by conditions such as heart valve disease, emphysema or bronchitis). Viagra was reported to prevent pulmonary hypertension but results were poorly presented.
Even if researchers were confident in the results of the study, it is unclear how the effects of sildenafil in healthy young men with acute hypoxia and pulmonary hypertension would relate to the effects of sildenafil in patients with chronic pulmonary hypertension who would probably be much older and have structural changes to the heart and/or lungs resulting from chronic illness.