Penile Injection Therapy: A Small Prick For A Bigger One

Andrew Siegel MD 3/5/2016

In 1983, at the American Urological Association meeting in Las Vegas, an event occurred that forevermore changed the field of male sexual dysfunction. Giles Brindley, a British physiologist, appeared from behind the podium and dropped his trousers, revealing to the audience his erection that had been induced by the injection of a medication directly into his penis. Commented one authority: “Farther down the Strip, Seigfried and Roy were making a white Bengal tiger disappear, and two circus aerialists—one sitting on the other’s shoulders—were traversing a tightrope without a net. But even in Vegas they’d never seen a show like this.” Few medical breakthroughs have had the dramatic effect that Brindley’s demonstration had, solidifying the principle that an erection is caused by smooth muscle relaxation in the erectile sinus tissues of the penis.


When first-line (healthy lifestyle) and second-line measures (ED meds, vibrational stimulation, penile pump)  are not sufficient in restoring erectile rigidity, penile injection therapy can be an effective and safe third-line option.

Penile injections of vasodilator drugs (medications that promote penile blood inflow) are beneficial for a wide range of medical conditions associated with ED. Vasodilator drugs injected directly into the penile erectile chambers bypass psychological, neurological, and hormonal factors and act locally on the erectile sinus tissues, causing blood to pour into the erectile chambers, inducing a rigid erection on demand. Injection therapy can be useful in ED due to psychological, neurological and hormonal causes as well as in men with some degree of blood vessel disease due to fatty plaque blocking arterial inflow. These injectable medications are the only such drugs that are capable of initiating an erection—in other words, achieving an erection without sexual stimulation.

A tiny needle is used to inject the medication into the side of the penis, directly into one of the paired penile erectile chambers. An erection usually occurs within 5-30 minutes and lasts for a variable amount of time, depending on the dosage of the medication. Injection-induced erections do not interfere with one’s ability to ejaculate or experience an orgasm.

Alprostadil (Caverject, Edex) is a commonly used vasodilator that increases penile blood flow and relaxes arterial and erectile sinus smooth muscle in the erectile chambers, resulting in a rigid erection. A combination of medications is often used to obtain optimal results. This combination is known as Trimix and consists of three drugs: Alprostadil, Papaverine and Phentolamine.

Who Knew? In 1982, French vascular surgeon Dr. Ronald Virag discovered the effect of Papaverine on erections when he mistakenly infused it into the penis, thinking he was administering saline. The patient immediately developed an erection and Dr. Virag realized that a new treatment for ED was possible.

Patients interested in using penile injection therapy are taught how to do the procedure during a urological office visit, at which time a test dose is administered. It is not a difficult technique to learn, although it requires some degree of dexterity. After learning the technique, the medication can be self-administered on demand. It often requires some trial and error to get the dosage just right so that the erection lasts an appropriate amount of time, in accordance with individual needs. With practice, one rapidly becomes skilled in the technique—not unlike learning to use contact lenses.

Side effects can be pain, bruising, scarring and prolonged erections. The most common side effect is a dull ache that is usually mild and tolerable. This typically happens with Alprostadil more commonly than with Trimix. A bruise may occur at the injection site and is best prevented by applying compression on the injection site for several minutes following the injection. Occasionally, a small lump can develop at the site of repeated injections and rarely penile scarring may be a consequence.

On occasion, a prolonged erection (priapism) may occur. It is undesirable to have an erection that lasts for more than four hours. If this occurs, it may require the injection of a medication to reverse the effects of the vasodilator drug and decrease penile blood flow in order to bring the erection down. This is safest done in an ER setting where cardiac monitoring can be performed.

Who Knew? Many male stars in the adult film industry use Trimix in order to achieve the erectile rigidity and durability necessary for their performances.

Sadly, there are some unscrupulous medical groups who prey on unsuspecting and vulnerable ED patients, often offering injection therapy without discussion of alternative treatments and charging patients exorbitant fees for medications such as Trimix.. See the following LA Times article concerning this:

The reality is that medications such as Trimix can be obtained via prescription from your urologist at reputable compounding pharmacies for very reasonable fees. It should not cost an arm and a leg to obtain a rigid penis!

Technique of Penile Injection

Preliminary tips:

  • Shave the base of the penis to make the process easier.
  • If possible, immediately before injecting, manipulate the penis to obtain some penile blood flow and filling.  The procedure will be easier with a plumper penis.
  • Avoid injecting into superficial veins.
  • The injection only needs to be done on one side even though there are two injection chambers, since they communicate.
  • Vary the injection site to avoid scarring.
  • Do not inject more than three times weekly.



(Author: Post Prostate, Source: Own work; 16 March 2013)

  1. If you are right-handed, use your left thumb to protect the 12 o’clock position (penile nerves) and your left index finger to protect the 6 o’clock position (urethral channel). If you are left-handed, use your right thumb to protect the 12 o’clock position (penile nerves) and your right index finger to protect the 6 o’clock position (urethral channel).
  2. Use an alcohol swab to cleanse the base of the penis in order to prevent infections and then set aside the swab and save.
  3. Holding the prefilled syringe like a pen, in dart-like fashion penetrate the skin of the penis at a right angle, passing the needle as far as it will go. The site should be between the 1 o’clock and 3 o’clock position for a righty and 9 o’clock and 11 o’clock position for a lefty. The base of the shaft is the easiest location for the injection; however, because the erectile chambers run all the way to the head of the penis, any shaft location is acceptable for the injection site.
  4. Inject the full contents of the syringe by applying pressure to the plunger.
  5. Remove the syringe and use the alcohol swab to apply pressure to the injection site for several minutes.
  6. Observe your penis becoming increasingly rigid and the rest is up to you!

Bottom Line:  Penile injection therapy can be an effective and safe option for restoring erectile function when first and second-line measures are not sufficient.

Wishing you the best of health,

2014-04-23 20:16:29

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Author of Male Pelvic Fitness: Optimizing Sexual and Urinary Health: available in e-book (Amazon Kindle, Apple iBooks, Barnes & Noble Nook, Kobo) and paperback:  In the works is The Kegel Fix: Recharging Female Pelvic, Sexual and Urinary Health.

Co-creator of Private Gym and PelvicRx: comprehensive, interactive, FDA-registered follow-along male pelvic floor muscle training programs. Built upon the foundational work of Dr. Arnold Kegel, these programs empower men to increase pelvic floor muscle strength, tone, power, and endurance: or Amazon.  

Pelvic Rx can be obtained at, an online store that is home to quality urology products for men and women.  Use code UROLOGY10 at check out for 10% discount. 










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11 Responses to “Penile Injection Therapy: A Small Prick For A Bigger One”

  1. Larry B Says:

    Nice article. I take issue with the “standard” advice to not use it more than 3 times/week…there doesn’t seem to be ANY data, or even a source article, to support that, though it is oft repeated.

  2. Practical Approach To Erectile Dysfunction | Our Greatest Wealth Is Health Says:

    […] Caverject and Edex (Prostaglandin E1) are vasodilators that when injected directly into the erectile chambers result in increased blood flow and erectile rigidity. After one is taught the technique of self-injection, the medication can be used on demand, resulting in rigid and durable erections.  A combination of medications can be used for optimal results– this combination is known as Trimix and consists of Papaverine, Phentolamine, and Alprostadil. […]

  3. Urethral Lozenge To Treat E.D.: What You Need to Know | Our Greatest Wealth Is Health Says:

    […] is significantly higher than when the medication is injected directly into the corpus cavernosum (penile injection therapy).  You may need to use a 1000 microgram pellet in the urethra, whereas if injected you might only […]

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    […] disease.  If full penile rigidity occurs after the injection of the vasodilator medication, a self-injection program becomes a viable potential option in the management of the ED.  Penile prosthesis implantation is […]

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    […] prostate surgery or from Peyronie’s: oral medications, traction therapy, vacuum suction therapy, injection therapy, etc.  Check in with your urologist for more information on these […]

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    […] cause), or due to a variety of underlying conditions including: perineal trauma, medications (vasodilator penile injections therapy for erectile dysfunction; trazodone; cocaine), hematological disorders (sickle cell disease), and […]

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    […] being brilliant advertising spin!  You are far more likely to encounter prolonged erections with penile injection therapy, a topic for another day.  There are numerous other causes for priapism, the medical term for a […]

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    […] management options include oral medications, traction therapy, vacuum suction therapy, injection therapy, penile implants, etc.,…check with your urologist for […]

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    […] In urology, the drug is often used for men with prolonged erections that may occur after penile injection therapy for erectile dysfunction. Because Sudafed constricts smooth muscle in the urethra, it can cause urinary difficulties, […]

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