An OTC drug will help patients get treatment more quickly. The Food and Drug Administration just granted over-the-counter sale marketing authorization for MED, a topical gel created to treat erectile dysfunction ED. There were some reports of headaches and nausea, however. They include dutasteride Avodart, Jalyn and finasteride Propecia, Proscar. Oral ED medicines might not work or might be dangerous if you also take any of the following: Nitrate medicines. They enhance the effects of a chemical the body makes that relaxes muscles in the penis, called nitric oxide. You can take it in a small dose daily or in a larger dose as needed.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 . Generic name: sildenafil (oral) [ sil-DEN-a-fil ] Brand names: Revatio, Viagra Drug classes: Agents for pulmonary hypertension, Impotence agents. Medically reviewed by Kaci . Tadalafil (Cialis). Vardenafil. These medicines are called PDE5 inhibitors. They enhance the effects of a chemical the body makes that relaxes muscles in the penis, called nitric .