If you are taking sildenafil to treat erectile dysfunction, follow your doctor’s directions and the guidelines in this paragraph. Be sure to let your doctor and pharmacist know that you are taking these medications before you start taking sildenafil. Sildenafil is in a class of medications called phosphodiesterase PDE inhibitors. Take sildenafil at around the same times every day. Sexual activity may be a strain on your heart, especially if you have heart disease. The products discussed in this site may have different product labeling in different countries.Price without insurance: starts at $80 per dose. Doses: 25, 50, and milligrams (mg) Supply: 30 or 90 days. To get a prescription for Viagra through the . 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 carrying blood to the . Extra 15% off $30 sitewide with code SAVE15; Clip your mystery deal! BOGO 50% off select Walgreens health & wellness.