An intracavernous injection is a medical treatment for erectile dysfunction (ED) that involves administering medication with a fine needle directly into the erectile tissues of the penis. This direct delivery increases local blood flow to produce an erection, bypassing the systemic circulation required by oral pills. Intracavernous injection is considered a second-line therapy, often recommended for individuals who have not had success with oral ED medications or cannot tolerate them.
How Intracavernous Injections Work
The medications used for intracavernous injections are vasodilators that relax the smooth muscle tissue inside the penis. This tissue is located in two sponge-like chambers called the corpora cavernosa, which run the length of the penis. When this smooth muscle relaxes, the arteries supplying blood to the penis widen, or dilate.
This dilation increases the volume of blood flowing into the corpora cavernosa. As these chambers fill with blood and expand, they compress the veins that drain blood away from the penis. This process of trapping blood within the penis causes a firm erection, which usually occurs within 5 to 20 minutes of the injection.
Several different medications can be used for this purpose. A common one is Alprostadil, a synthetic version of prostaglandin E1. Combination formulas are also frequently prescribed, such as BiMix, which contains papaverine and phentolamine, or TriMix, which adds alprostadil to the other two ingredients.
The Injection Procedure
The first step is gathering the necessary supplies, including the medication vial, a sterile single-use syringe, and alcohol swabs. After cleaning the top of the vial with an alcohol swab, the correct dosage prescribed by a healthcare provider is drawn into the syringe.
The injection should be administered into the base of the penis shaft, avoiding the top, bottom, and the midline. The target area is on the side of the shaft, at the 2 to 3 o’clock or 9 to 10 o’clock position. Avoid any visible veins or arteries to minimize bleeding and bruising. Patients are instructed to alternate the side of the penis for each injection to reduce the risk of tissue changes.
The selected site is cleaned with an alcohol swab before the needle is inserted at a 90-degree angle into the spongy tissue of the corpora cavernosa. The plunger is then pushed to deliver the medication. After withdrawing the needle, apply firm pressure to the injection site for several minutes to prevent bruising or bleeding. The first injection is often done in a clinical setting under the supervision of a nurse or doctor to ensure the patient understands the technique correctly.
Potential Side Effects and Risks
The most common side effects are localized to the penis and include a dull ache or pain, and minor bleeding or bruising at the injection spot. These symptoms are typically transient and resolve on their own. Applying pressure after the injection can help minimize some of these effects.
A less common but more serious risk is the development of penile fibrosis. This condition involves the formation of hard, fibrous scar tissue within the erectile chambers. It can result from repeated injections into the same area over a long period.
The most significant risk associated with these injections is priapism. This is a persistent, often painful erection lasting more than four hours that is unrelated to sexual stimulation. Priapism is a medical emergency because prolonged pressure can deprive penile tissues of oxygen, leading to permanent damage. An erection lasting four hours requires immediate medical attention.
Efficacy and Patient Considerations
Intracavernous injections have a high success rate, producing a functional erection in over 80% of users. Its effectiveness extends to men who do not respond to oral medications due to conditions like poor vascular health or nerve damage, such as that resulting from prostate surgery.
Good candidates for this therapy are often men for whom oral treatments have failed or caused unacceptable side effects. It is also used in erectile rehabilitation programs following radical prostatectomy to help prevent muscle atrophy in the penis.
However, this treatment is not suitable for everyone. Individuals should not use this therapy if they have certain conditions, including:
- A history of priapism
- Blood disorders such as sickle cell anemia or leukemia
- A known allergy to the medication
- Difficulty with manual dexterity due to arthritis or other issues
A discussion with a healthcare provider is necessary to determine if this therapy is an appropriate and safe option.