Some men with erectile dysfunction elect to use penile injection therapy, which is also known as intracavernosal injection therapy. This treatment approach involves injecting medications directly into the penis. The technique is easy to learn, but it should be taught and demonstrated by a healthcare professional, such as doctor, nurse, or sexual medicine clinician, before men try it alone at home. Monitoring of the dose by a healthcare professional is also necessary in the beginning until the optimal dose can be determined, based on a man’s response to the medication.
Injections can be made into the base or side of the penis, but the least sensitive spot on the penis is the middle of the shaft on either side. Many men express anxiety over the prospect of injecting their penis with a needle. However, because the needle is very fine and only about one-half inch in length, the pain is minimal, similar to injecting yourself with insulin. Some medications are available in pre-filled syringes, while others require that you draw them up into the syringe yourself from a vial.
Basically, the injection process goes like this. Take the pre-filled or self-prepared syringe and remove the cap. Place the syringe on a surface so that the needle stays clean. With the non-dominant hand, grab the penis at the head and stretch it. With the dominant hand, wipe injection site with an alcohol swab. While the penis is stretched, inject the needle at a 45-degree angle into the middle of the shaft on either side. Once the needle is all the way in, press the plunger and remove the needle. Use an alcohol swab to apply pressure to the injection site with the thumb of the non-dominant hand while also applying pressure on the opposite side of the shaft with the index finger. Keep applying pressure for three to five minutes.
An erection should occur within 5 to 15 minutes, depending on which medication is used and how anxious the man is. Men who are nervous usually take longer to achieve an erection because their adrenaline levels are counteracting the medication. Thus the first few times a man uses penile injection therapy, he may take a little longer to achieve an erection because he is anxious.
Some side effects from injecting the penis may include bruising on the penis, bleeding from the injection site, a prolonged erection (priapism; lasting longer than four (4) hours), and the development of fibrous tissue at the injection site, but these are not common. Men should alternate sides when doing the injections to minimize side effects. Applying pressure to both sides of the penis after the injection for at least three minutes is important to prevent bruising. The risk of infection is very low, especially if you are diligent about using an alcohol swab. The possibility of scarring the erection tissue or the tunica, known as Peyronie’s disease, is extremely low when the injections are used properly.
The possibility of priapism is a side effect men sometimes ask about. Men can prevent priapism by adhering to the dose prescribed by their healthcare provider and not increasing the dose on their own because they are not pleased with the quality of their erection. Any increases in dosing should be discussed with a physician before they are attempted. Priapism is a serious medical condition, because the penis is deprived of oxygen, which damages and destroys erectile tissue.
The most commonly used medication for penile injection therapy is alprostadil (Caverject), a synthetic version of a hormone called prostaglandin E. This hormone has the ability to relax the muscles in the penis, which improves the blood flow necessary for an erection. Alprostadil can produce an erection in 5 to 20 minutes, and it can last for about 60 minutes or longer, although the average is about 30 minutes. About 60 percent of men with erectile dysfunction respond to alprostadil injections, including men who have undergone prostatectomy and radiation therapy. A possible side effect associated with alprostadil in men who have damage to their cavernous nerve (which includes men who have had a prostatectomy or who have diabetes) is pain. This can occur because the penis in such men is overly sensitive to prostaglandin. The pain is mild in some men but severe in others.
Another medication used in penile injections is Trimix. Response to this drug is better than with alprostadil—greater than 90 percent—although a drawback is that unlike alprostadil, which is available in pre-filled syringes, men have to draw up their own syringes for Trimix. Trimix is a combination of three ingredients: papaverine, phentolamine, and prostaglandin E. Because the amount of prostaglandin E is much less than in Caverject, the possibility of pain associated with the prostaglandin is nearly eliminated. For men who are very sensitive and still experience some pain or burning in the penis with Trimix, another drug called Bimix, which contains only papaverine and phentolamine, can be used.
When it comes to cost, Caverject is typically covered by insurance, while Trimix and Bimix usually are not. For men who must pay for their drugs out of pocket, Caverject can prove to be expensive, because each injection is about $20. Comparatively, a vial of Trimix can cost about $85 and last several months. The bottom line, however, is finding the drug that works best for you, and then shopping around for the best price from a reliable source.
CAUTION about 4 Hour Erections!
The advertisements on TV for the major ED drugs always advise you to “seek medical attention if you have an erection lasting longer then 4-hours”. One side effect from drugs to treat ED can be a prolonged erection (known as priapism; an erection lasting longer than four hours). A prolonged erection may also be caused by other treatments such as injections and MUSE suppositories.
Priapism is a serious medical condition, because the penis is deprived of oxygen, which damages and destroys erectile tissue. These warnings should be taken seriously and medical attention sought immediately. Often times, your doctor may give you an information card similar to the Sloan-Kettering Wallet Card for patients using penile injections. This card details the serious nature of priapism and advises the attending medical professional of treatment options and other information.