Injections or Topical Treatments:

Treatments Using Alprostadil

Alprostadil is derived from a natural substance, prostaglandin E1, which opens blood vessels. This medicine is an effective treatment for some men. It can be administered by:

• Injection into the erectile tissue of the penis (such as Caverject or Edex)
• A system that administers the drug in pellets placed in the urethra (MUSE system)

Candidates. Alprostadil is not an appropriate choice for men with:

• Severe circulatory or nerve damage
• Bleeding abnormalities or men who are taking medications that thin the blood, such as heparin or warfarin
• Penile implants

Injected Alprostadil. Injected alprostadil (Caverject, Edex) uses a very small needle that the man injects into the erectile tissue of his penis. About 80% of men describe the pain of administering the injection as very mild.

The drug should not be injected more than 3 times a week or more than once within a 24-hour period.

MUSE System. The MUSE system delivers alprostadil through the urethra. It works in the following way:

• The device is a thin plastic tube with a button at the top.
• The man inserts the tube into his urethral opening right after urination. (Urinating or urine leakage right after administration may reduce the amount of medication.)
• He presses the button, which releases a pellet containing alprostadil.
• The man rolls his penis between his hands for 10 - 30 seconds to evenly distribute the drug. To avoid discomfort, the man should keep the penis as straight as possible during administration.
• The man should be upright, (sitting, standing or walking), for about 10 minutes after administration. By that time, he should have achieved an erection that lasts 30 - 60 minutes. (If a man lies on his back too soon after administration, blood flow to the penis may decrease and the erection may be lost.)
• The erection may continue after orgasm.

The MUSE system should not be used more than twice a day and is not appropriate for men with abnormal penis anatomy.

Side Effects of Most Alprostadil Methods. Certain side effects are common to all methods of administration, although they may differ in severity depending on how the drug is given:

• Pain and burning at the application site.
• Scarring of the penis (Peyronie's disease), which is most likely to occur with injections.
• Sudden, low blood pressure. Symptoms include dizziness, lightheadedness, and fainting. If these symptoms occur, the man should lie down immediately with his legs raised.
• Priapism (prolonged erection). Possible with any method, but less chance with the MUSE system than with injections. If priapism occurs, applying ice for 10-minute periods to the inner thigh may help reduce blood flow. Erections that last 4 hours or longer require emergency care.
• Women partners may experience vaginal burning or itching. The drug may have toxic effects if it reaches the fetus in pregnant women, so men should not use alprostadil for intercourse with pregnant women without the use of a condom or other barrier contraceptive device.
• Other side effects include minor bleeding or spotting, redness in the penis, and aching in the testicles, legs, and area around the anus.

Injections Using Papaverine and Phentolamine

Until the introduction of alprostadil, the two drugs used for injection therapy had been papaverine (Pavabid, Cerespan) and phentolamine (Regitine). Adverse reactions are usually minor but include pain, ulcers, and prolonged erections (priapism). These drugs are rarely used now.

Testosterone Replacement Therapy

Testosterone replacement therapy works best for men with ED who have been diagnosed with hypogonadism (low testosterone levels). Men who have ED and normal testosterone levels are not likely to benefit from testosterone therapy. Studies indicate that testosterone therapy can modestly improve erectile function and libido.

Forms of testosterone therapy include:

• Muscle injections using testosterone enanthate (such as Andryl or Delatestryl) or cypionate (Andro-Cyp, Depo-Testosterone, or Virion).
• Skin patch (Testoderm, Testoderm TTS, Androderm). Depending on the brand, patches may be applied daily to the skin of the scrotum or to the abdomen, back, thighs, or upper arm.
• Skin gel (such as Androgel or Testim). The gel is applied only to the shoulders, upper arms, or abdomen, not directly to the penis. It is extremely important that men thoroughly wash their hands with soap and water after applying the gel, and cover the application site with clothing once it dries. Testosterone gel has caused serious side effects (premature development, genital enlargement) in children who have come in contact with it through secondary exposure. Pregnant women must avoid contact with the gel because the testosterone can harm the fetus.
• Oral forms of testosterone are not recommended because of the risk for liver damage when taken for long periods of time.

Side effects may include acne, breast enlargement, headache, and emotional instability. Testosterone therapy may increase the risk for the following serious side effects:

• Rapid growth of prostate tumors in men with existing prostate cancers. (Taking testosterone does not appear to increase the risk for prostate cancer, but doctors remain concerned.)
• Benign prostatic hyperplasia (BPH), enlargement of the prostate gland
• Liver disease and possibly liver cancer
• Worsening of sleep apnea, especially in men who are obese or who have lung conditions