There are a variety of options that may successfully treat erectile dysfunction, but each treatment may have its own set of side effects. One common treatment for ED is oral medication, including tadalafil, sildenafil, and vardenafil. These drugs may increase blood flow to the penis, but they can also have side effects such as headaches, upset stomach, and vision problems. Certain people may experience more serious side effects like dangerously low blood pressure or painful, long-lasting erections. Because of this, people with very low or high blood pressure, or people with heart disease or uncontrolled diabetes, shouldn't take these drugs. Other medications like alprostadil may be injected or inserted into the penis. These types of drugs are much less likely to cause side effects, but if they do occur they may include bleeding or pain at the site of injection or insertion and the formation of fibrous tissue in the penis. Talk to your doctor if you develop any new symptoms while undergoing treatment for erectile dysfunction.