The primary indication of sildenafil is treatment of erectile dysfunction (inability to sustain a satisfactory erection to complete intercourse). Its use is now one of the standard treatments for erectile dysfunction, including for men with diabetes mellitus.
Antidepressant-associated sexual dysfunction
Tentative evidence suggests that sildenafil may help men who experience antidepressant-induced erectile dysfunction.
While sildenafil improves some markers of disease in people with pulmonary arterial hypertension, it does not appear to affect the risk of death or serious side effects as of 2014.
Sildenafil and other PDE5 inhibitors are used off-label to alleviate vasospasm and treat severe ischemia and ulcers in fingers and toes for people with secondary Raynaud’s phenomenon; these drugs have moderate efficacy for reducing the frequency and duration of vasospastic episodes. As of 2016, their role more generally in Raynaud’s was not clear.
High-altitude pulmonary edema
Sildenafil has been studied for high-altitude pulmonary edema but its use is currently not recommended for that indication.