Penile Injection Therapy (Intracavernosal Injection): Who Is It For?
How is intracavernosal injection therapy — considered in erectile dysfunction that does not respond to oral medication — administered, who is it suitable for, and where is caution needed?
Treatment for erectile dysfunction is planned as a series of steps. When lifestyle measures and oral medication do not provide enough benefit, one of the options assessed before moving to surgery is injection therapy applied to the penis. Known in medical terms as intracavernosal injection, this method is based on delivering medication directly into the erectile tissue.
Because of its name, the method initially makes most patients hesitant; the phrase “an injection into the penis” naturally suggests pain and difficulty. When taught properly, however, it is a form of treatment patients can administer themselves and one that does not markedly restrict daily life. This article covers how injection therapy works, who it is suitable for, how the technique is taught and where caution is needed.
How does intracavernosal injection work?
Inside the penis are two spongy structures that produce an erection, known as the corpora cavernosa. In injection therapy a drug with a vasodilating effect is delivered directly into this tissue through a fine needle.
The drug relaxes the muscle in the vessel walls and increases blood flow into the penis; the filled tissue compresses the veins from within and rigidity develops. This is the most important difference from oral medication: here the effect arises directly at the level of the blood vessels, without waiting for the chain triggered by sexual stimulation to begin.
Injection therapy can therefore be effective in patients with nerve damage or in those who do not respond adequately to oral drugs. Onset is generally rapid, and duration varies with the drug used, the dose and the individual.
Who may be suitable?
Injection therapy is not recommended for every man with erectile dysfunction; it generally comes into consideration in particular situations:
- Those not responding to oral medication: Patients who do not achieve an adequate result despite several attempts at an appropriate dose.
- Those unable to take oral medication: Patients for whom oral treatment is unsuitable, for example because they take nitrate medication for heart disease.
- Those with erectile dysfunction due to nerve damage: The period after radical prostate surgery, or nerve involvement due to advanced diabetes.
- Those in rehabilitation after surgery: Selected cases where the physician considers it appropriate to support regular blood flow to the tissue after prostate surgery.
- Patients needing diagnostic assessment: It is also used to assess the vascular response during a penile Doppler ultrasound examination.
By contrast, careful assessment is needed in patients with a bleeding disorder, those taking certain blood thinners, those with advanced tissue scarring (fibrosis) in the penis, or those with a history of priapism. Where manual dexterity is markedly limited, who will administer the injection is planned separately.
How is the technique taught?
In patients starting injection therapy the first administration is carried out under medical supervision. This first session matters both for dose adjustment and for safety.
The process generally includes the following steps:
- Determining the dose: Treatment begins at a low dose; the response is assessed and the dose adjusted to the individual.
- Showing the injection site: Which part of the penis is used and at what angle is demonstrated; the upper and lower surfaces, where vessels and nerves are concentrated, are avoided.
- Hygiene rules: Skin cleaning, single-use needles and applying pressure afterwards are explained.
- Rotating the site: Not using the same point each time is important in reducing the risk of tissue scarring.
- Frequency limit: The number of injections per week is specified by the physician and should not be exceeded.
After the first administration, most patients say the method is easier than they expected. The very fine needle used is one of the factors that makes the procedure easier.
Is it painful, and what are the side effects?
A mild stinging sensation may be felt during administration; some patients experience a feeling of fullness or mild pain from the effect of the drug. This sensation is usually short-lived.
The side effects to be aware of are:
- Bruising at the injection site: Usually resolves on its own; hygiene and correct technique reduce how often it occurs.
- Pain: May vary with the drug used; where pain persists, a change of dose or drug is considered.
- Tissue scarring (fibrosis): The risk increases with repeated injections into the same area, which is why rotating the site matters.
- Prolonged erection: This is the most important risk of the method and needs to be addressed separately.
Why does the risk of prolonged erection (priapism) matter?
The situation requiring most attention in injection therapy is an erection lasting longer than expected. A painful erection that continues independently of sexual stimulation and lasts for hours is called priapism and requires urgent assessment.
In a prolonged erection the oxygenation of the tissue is impaired; without intervention, permanent tissue damage can develop. Patients are therefore told clearly when treatment begins that they must attend a healthcare facility without delay if an erection exceeds a specified duration, and that duration is stated by the physician.
This risk is the main reason the dose is determined under medical supervision and why patients must not increase the dose on their own initiative. With the correct dose and proper technique, this situation is uncommon.
Is injection therapy a lasting treatment?
Injection therapy does not remove the underlying cause of erectile dysfunction; it is a supportive treatment applied when needed. Its effect is therefore limited to each administration and it requires regular use.
Some patients continue this treatment without difficulty for a long period. Others do not wish to continue over time; discomfort with using a needle, a reduced sense of spontaneity or a decline in response can all play a part in that choice. The notable rate of discontinuation shows that this method is not a long-term answer for everyone.
In patients who do not benefit from injection therapy, or who do not wish to continue it, penile implant surgery is assessed as the next step. Injection therapy is therefore often seen as a stage tried before moving to surgery, one that also helps the patient clarify their own preference.
What should be considered when starting treatment?
Several points stand out in continuing injection therapy safely:
- The first administration must be carried out under medical supervision and the dose determined by the physician
- The dose must not be increased on the patient's own initiative
- The weekly number of injections specified by the physician must not be exceeded
- A single-use needle should be used each time and the site rotated
- Medical review must be sought without delay for an erection exceeding the stated duration
- A follow-up appointment should be made if hardness, curvature or a palpable irregularity is noticed in the penis
Injection therapy applied to the penis is a step that can be effective in patients who do not gain enough benefit from oral medication, and one assessed before surgery. Teaching the technique under medical supervision, determining the dose individually and informing the patient about prolonged erection are the essential conditions for carrying out this treatment safely. Assoc. Prof. Dr. Zülfü Sertkaya practises in urology and andrology in Istanbul; planning the treatment steps in erectile dysfunction is carried out with individual assessment and confidentiality.