Patient Guide to Penile Injections

Although you probably find the idea of injecting something into your penis unappealing, many men are highly satisfied with this therapy and will testify to the ease and effectiveness of the injections. Before using the therapy on your own at home, your doctor will show you how to inject the medication. Improper injection and any subsequent scarring can lead to penile curvature and nodules in the penis, so it is important to get proper training before beginning injection therapy.

How Medication Is Injected

The medication is injected along either lateral side of the penis. First, the medication is drawn into a syringe, usually an insulin-type syringe with a short, very fine needle. The medication is given into the spongy tissue of the penis, called the corpora cavernosa.

After choosing the proper site to inject on your penis, clean it with an alcohol wipe, "poke" the needle through the skin of the penis, and then inject the medication into the penis. Immediately afterwards, press firmly on the injection site with either an alcohol pad or gauze with your thumb and first finger to compress the area for at least five minutes or up to 10 minutes for patients taking blood thinning medication, such as coumadin.

The medication tends to work better if you stand, as it allows more blood to go to your penis. Also, external stimulation to the penis increases blood flow to the penis and allows the medication to take effect faster.

Some people prefer the auto-injector, which is a spring-loaded device that inserts the needle into the penis very quickly, minimizing discomfort and psychological "hesitancy." It comes in two forms: a simple, non-prescription device designed to insert the needle for you, and a prescription device that also depresses the plunger for you.

Check with your local drug store for the non-prescription simple auto-injector. Many men prefer the auto-injector that does not inject the medications for them, because they maintain the necessary feel to know that they have injected in the right place and to the right depth.

Side Effects

Occasionally, penile injections can cause fainting, dizziness and low blood pressure. In rare instances, priapism or prolonged erections can occur. Patients who are not trained properly may experience pain, infection, bruising and scarring.

Things to Remember

  • After inserting medication, self-stimulation may be necessary to increase blood flow to your penis.
  • If your erection persists for more than four hours, seek medical care at a local emergency room or from your urologist.
  • Penile injections may be ineffective in patients who have vascular disease or blood flow problems.


Reviewed by health care specialists at UCSF Medical Center.

This information is for educational purposes only and is not intended to replace the advice of your doctor or health care provider. We encourage you to discuss with your doctor any questions or concerns you may have.

Related Information

UCSF Clinics & Centers

Urology Practice
400 Parnassus Ave., Sixth Floor, Suite A610
San Francisco, CA 94143
Phone: (415) 353-2200
Fax: (415) 353-2641