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Understanding Erectile Dysfunction Medications (cont.)

Penile Injections (Prostaglandins)

Prostaglandins include alprostadil (Caverject, Edex, Muse Pellet).

  • How prostaglandins work: These drugs work by enhancing blood flow to the penis, thereby causing erection. Alprostadil (Caverject, Edex, Muse Pellet) is a naturally occurring prostaglandin E1 synthetically manufactured for commercial use. Alprostadil is a vasodilator that induces erection by relaxing smooth muscle and widening arteries that supply blood to the penis. Increased blood supply to the penis facilitates erection.
  • Who should not use these medications: Persons with allergy to alprostadil should not take them, nor should persons with hyaline membrane disease, respiratory distress syndrome, penile implants or an abnormally formed penis, or conditions resulting in long-lasting erections (for example, sickle cell anemia or trait, leukemia, or multiple myeloma).
  • Use: Prostaglandins are administered as either an injection into the penis or as a pellet inserted into it (via the urethral opening at the end of the penis).
  • Drug or food interactions: No drug or food interactions are currently known.
  • Side effects: A prolonged erection lasting more than four hours may occur, and if this occurs a physician should be contacted. Prostaglandins may cause headache, decreased blood pressure, or dizziness. Caution is warranted in individuals with heart disease that may be aggravated by decreased blood pressure.

Phentolamine and papaverine injection: These medications have been prescribed for many years and are very effective and inexpensive. Both of these drugs are used for other diseases, but the US Food and Drug Administration has not formally approved them for treating erectile dysfunction. Prostaglandin, phentolamine, and papverine are often combined and prescribed as Trimix.

Investigational Drugs

The following drugs are currently undergoing investigation for use in treating erectile dysfunction:

  • Phentolamine (Regitine) and papaverine (Genabid, Pavabid, Pavatine) injection: This therapy has been prescribed for many years. Both of these drugs are used for other diseases, but the US Food and Drug Administration has not formally approved them for treating erectile dysfunction. Phentolamine has recently been in short supply, and the introduction of newer, effective drug therapy has limited use of this combination.
  • Apomorphine (Uprima)
  • PT-141 (a melanocortin receptor activator given as a nasal spray)
  • Alprostadil cream (Alprox-TD)

Medically reviewed by Michael Wolff, MD; American Board of Urology


Food and Drug Administration Prescribing Information.

Medically Reviewed by a Doctor on 5/26/2016
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