Finally, we checked customer reviews to better understand user experiences with each platform. Do not take other medicines unless they have been discussed with your doctor. The amount of medicine that you take depends on the strength of the medicine. Tell your doctor if any of these symptoms are severe or do not go away: headache. We offer almost every brand of erectile dysfunction medication offered in the United States, including Viagra, Cialis, and Levitra. Medications for erectile dysfunction can be very effective for patients who experience mild to moderate erectile dysfunction.To treat erectile dysfunction-ED, take this drug by mouth as directed by your doctor, usually as needed. Take sildenafil at least 30 minutes, but no more than 4 hours, before sexual activity (1. 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 . Viagra comes as an oral tablet in different dosages. Discuss with your doctor what’s an appropriate dose for you. For daily use, Goldstein said, the generic form, sildenafil, comes in mg tablets.