Pearlman says. The four main medicines taken by mouth for erectile dysfunction are: Avanafil Stendra. When oral medications might not be safe Check with your health care team before you take any medicine for erectile dysfunction. It might be a while before MED is available at your local pharmacy. This medication is taken with or without food an hour before sex.Generic name: sildenafil (oral) [ sil-DEN-a-fil ] Brand names: Revatio, Viagra Drug classes: Agents for pulmonary hypertension, Impotence agents. Medically reviewed by Kaci . Sildenafil (Viagra, Revatio) is a moderately priced drug used to treat erection problems in men. It is also used to treat pulmonary arterial hypertension, a serious heart and lung . Drug Images What is Viagra? If you have erectile dysfunction (ED), your doctor may recommend that you take Viagra. It’s a prescription drug that’s used in adult males* with .