Your doctor or other health care professional can recommend one for you based on these factors, other health conditions you have and any other medicines you take. These include itraconazole Sporanox, Tolsura , ketoconazole Extina, Ketozole, others and ritonavir Norvir. They include dutasteride Avodart, Jalyn and finasteride Propecia, Proscar. However, one of the easiest, most effective, and best-known treatments for erection problems is Viagra. This medicine works best when you take it on an empty stomach an hour before sex. Severe liver disease.Sildenafil (Viagra). Tadalafil (Cialis). Vardenafil. These medicines are called PDE5 inhibitors. They enhance the effects of a chemical the body makes that relaxes . By Ginger Skinner Last updated: June 14, If you’re looking for a less costly Viagra, you might want to ask your doctor about sildenafil. It’s the active ingredient . 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 .