Alprostadil, which is marketed under the product name Edex®, is primarily prescribed to treat erectile dysfunction. The drug works by temporarily relaxing muscles in and increasing blood flow to the penis. It has also been used to treat infants who have ductal-dependent congenital heart disease.
The drug contains a prostaglandin (PGE-1) that relaxes the muscles of the penis. It also helps to widen the blood vessels so that more blood flow will reach the penis. These two temporary conditions will usually result in an erection. When the medication wears off, the blood flow and muscles return to their usual state and the erection should go away.
Alprostadil is administered via injection into the penis. It usually works within several minutes and up to 20 minutes after it is injected. The drug will typically remain effective from about 30 minutes to one hour. It is not meant to be used more than three times in a week, or more than once over the course of a 24-hour period.
If an erection obtained from taking alprostadil lasts longer than four hours, medical attention should be sought immediately. It could be a condition called priapism in which the blood cannot drain from the penis. Damage from this condition can be permanent if it is not treated promptly.
There are several conditions which make taking alprostadil too risky. They include any problems with blood or bone marrow such as leukemia, sickle cell anemia, or multiple myeloma. Penile abnormalities, deformation, or implants can also be problematic. Any condition with an increased risk of a painful or prolonged erection such as priapism may also make taking the drug too risky. It is also not advisable to take the drug if it is too physically risky for the patient to engage in sexual intercourse.
The most common side effects of alprostadil do not require doctor attention unless they persist or become more severe. There is a possibility of a mild amount of bleeding where the drug is injected. Some patients also experience a mild pain in the genitals.
There are also several rare, but severe, side effects possible from taking alprostadil that should be reported to a medical professional as soon as possible. They include blood or discharge coming from the tip of the penis, bloody urine, and any tenderness or inflammation that arises as a result of injecting the drug. Some patients may also faint, feel dizzy, or have an irregular or fast heartbeat. Severe genital pain or painful erections are also serious side effects.