Do you get erections during masturbation, with a partner or while you sleep? If too much is used, the chance of side effects is increased. A family doctor will recommend one if necessary. This medication is taken with or without food an hour before sex. What’s the best treatment? Often, these are prescribed for chest pain called angina. After discussing your erectile dysfunction and your medical history, ask your doctor for a prescription for Viagra. · Adults 65 years of age and older—25 mg as a single dose no more than once a day, 1 hour before sexual intercourse. Alternatively, the medicine may be taken 30 . Viagra is used to treat erectile dysfunction (impotence) in men. Another brand of sildenafil is Revatio, which is used to treat pulmonary arterial hypertension and . Generic Viagra (sildenafil) is an alternative to the branded Viagra drug that can be used for treating erectile dysfunction (ED). It’s now sold by many manufacturers, .