These include itraconazole Sporanox, Tolsura , ketoconazole Extina, Ketozole, others and ritonavir Norvir. These are commonly prescribed for an enlarged prostate or male pattern baldness. Generic versions of sildenafil, vardenafil and tadalafil are available. The body takes longer to absorb it after a high-fat meal or alcohol. Oral ED medicines might not work or might be dangerous if you also take any of the following: Nitrate medicines. These include a heart attack, stroke or a serious heart rhythm disorder in the past six months. Oral medicines for ED usually work well and cause few side effects.ID your medication Need drug interactions info? Learn how your medication interacts with other prescriptions, over-the-counter (OTC) drugs and/or supplements. Check Drug Interactions. There are four types of ED pills on the market, including sildenafil and tadalafil, often known by their brand names, Viagra and Cialis. We compare ED pills in terms of effectiveness, cost, side. Oral medicines for ED usually work well and cause few side effects. The four main medicines taken by mouth for erectile dysfunction are: Avanafil (Stendra). Sildenafil (Viagra). Tadalafil (Cialis). Vardenafil. These medicines are called PDE5 inhibitors.