There have been rare reports of priapism (prolonged and painful erections lasting more than six hours) with the use of PDE5 inhibitors such as sildenafil, vardenafil, and tadalafil. Patients with blood cell diseases such as sickle cell anemia, leukemia, and multiple myeloma have higher than normal risks of developing priapism. Untreated priapism can cause injury to the penis and lead to permanent impotence. Therefore, if your erection lasts four hours, you should seek emergency medical care.
For an algorithm to facilitate evaluation and treatment of patients with ED, see figure 2.

It is important to remember that having sex can put additional strain on the heart and may increase your risks if you have a history of heart disease or have an existing heart problem. The most common side effects of erectile dysfunction treatments include headaches, a sudden feeling of heat in your upper body, indigestion, visual disturbances, dizziness or a stuffy nose. Side effects are usually mild to moderate and don’t last long. If you experience any side effects or perhaps an increase in the severity of a side effect, you should stop taking the medication.
Talk with your doctor before trying supplements for ED. They can contain 10 or more ingredients and could make other health conditions worse. Some men say alternative treatments help them get and keep an erection. Unfortunately, the long-term safety of these products isn’t known, so most doctors don’t recommend them.