Intracavernosal injection (ICI) therapy is a medical treatment for erectile dysfunction (ED), where medication is administered directly into the penis to induce an erection. This method is often recommended when oral medications are not effective or suitable. The goal is to provide a reliable way to achieve an erection sufficient for sexual activity. In use since the early 1980s, ICI is considered a second-line therapy for ED. It is a localized treatment, meaning the medication acts on penile tissues with minimal systemic effects, and is effective for ED caused by various factors like neurogenic or diabetic conditions.
How Intracavernosal Injections Work
The medications used in ICI are vasodilators. When injected into the corpus cavernosum, the sponge-like erectile tissue of the penis, these drugs relax the smooth muscle. This relaxation allows the arteries within the penis to widen, increasing the volume of blood flowing in. Simultaneously, the expanding erectile tissue compresses the veins that would normally drain blood away.
This combination of increased inflow and reduced outflow of blood causes the penis to become firm, resulting in an erection that begins within 5 to 15 minutes. The process bypasses the nerve signals and hormonal pathways required for a natural erection. This direct action is why ICI can be effective even when ED is related to nerve damage or poor blood vessel function.
The ICI Procedure and What to Expect
ICI therapy begins with a consultation with a urologist. During this initial appointment, the doctor will determine if you are a suitable candidate and conduct the first injection in the office. This test dose allows the physician to identify the correct medication and dosage, and it also serves as a training session.
The medical team provides instruction on how to handle the medication, select the proper injection site, and perform the injection safely. Patients learn to draw the correct dose into a very fine needle, similar to what is used for insulin injections, with a common size being a 31-gauge needle.
When performing the injection at home, the process involves cleaning the injection site with an alcohol swab. The injection is administered into the corpus cavernosum, avoiding visible veins and the urethra. After injecting the medication, firm pressure is applied to the site for a few minutes to prevent bruising.
Common Medications for ICI
The most frequently prescribed single medication for ICI therapy is Alprostadil, a synthetic form of prostaglandin E1. It is the only medication specifically approved by the Food and Drug Administration (FDA) for this purpose.
For many individuals, compounded mixtures of medications provide a more potent or tailored response. Urologists often prescribe these combinations to enhance effectiveness and reduce side effects. These mixtures are commonly known by names like Bimix, which contains papaverine and phentolamine. Trimix, the most common combination, adds Alprostadil to the papaverine and phentolamine mixture. Although these compounded medications are widely used, they are not individually FDA-approved, which means dosing and formulation can vary.
Potential Side Effects of ICI Therapy
While safe when administered correctly, ICI therapy does carry potential side effects. The most common issues are localized to the injection site, including mild pain, swelling, or bruising. Some men may also experience a temporary burning sensation immediately following the injection.
A more serious, though less common, complication is priapism. This is a prolonged erection that lasts for more than four hours and is not related to sexual stimulation. Priapism is a medical emergency that requires immediate attention from a doctor to prevent permanent damage to the erectile tissue.
Over long-term use, there is a risk of developing penile fibrosis, which is the formation of scar tissue inside the penis. This can manifest as hard nodules or cause the penis to curve when erect, a condition known as Peyronie’s disease. Alternating the injection site for each use is an important part of proper technique to reduce the likelihood of fibrosis. Regular follow-up appointments with a urologist are recommended to monitor for any changes.