To provide you with the most relevant and helpful information, and understand which information is beneficial, we may combine your email and site usage information with other information we have about you. Some medications should not be taken with sildenafil. Sildenafil usually should not be taken more than once every 24 hours. Take sildenafil at around the same times every day. If you become pregnant while taking sildenafil, call your doctor. Talk to your doctor about eating grapefruit and drinking grapefruit juice while taking this medicine. Sildenafil may cause side effects.$ retail Save 91% $ Get free savings Most popular Safeway $ retail Save 94% $ Get free savings Low price Walgreens $ retail Save 94% $ Get free savings directions Closest store Rite Aid. Find patient medical information for sildenafil oral on MD including its uses, side effects and safety, interactions, pictures, warnings and user ratings. (including prescription drugs. Sildenafil (Viagra) is used to treat erectile dysfunction (impotence; inability to get or keep an erection) in men. Sildenafil (Liqrev, Revatio) is used to improve the ability to exercise in adults (Liqrev, Revatio) and children 1 year of age and older (Revatio) with pulmonary arterial hypertension (PAH; high blood pressure in the vessels.