Vasodilators to Manage Erectile Dysfunction

Andrew Siegel MD   10/10/2020

When ED has failed to respond well to conservative measures—healthy lifestyle, pelvic floor muscle training, oral ED meds, mechanical devices, etc.—there are alternatives that can effectively restore erectile function.  Today’s entry reviews penile vasodilator therapy, the use of medications applied directly into the penis to relax and expand the penile blood vessels, causing a surge of blood flow and inducing an erection.  These options are not for the feint of heart since the application involves either placing a substance within the urethra, or alternatively, using a small syringe and needle to inject the medication directly into one of the erectile chambers.


MUSE (medicated urethral system for erection) is a pellet of a vasodilator medication that is placed within the urethra (urinary channel) to increase penile blood flow and induce an erection. MUSE consists of prostaglandin E1 (Alprostadil) lozenges—available in 125, 250, 500, and 1000 microgram dosages. Absorption occurs through the urethra into the adjacent erectile chambers. The onset of MUSE is 15 minutes or so, and when effective, the erection will last for about one hour. Unfortunately, MUSE is only of benefit to about one-third of users.

The fundamental problem with MUSE is that it is placed in the urethra, which has little role in erectile function. The urethra is surrounded by one of the erectile chambers (a.k.a. “spongy body”) that becomes tumescent (plump) at the time of an erection, but it never achieves the rigidity of the paired erectile chambers (a.k.a. cavernous bodies). The neighboring erectile chambers are the paired structures that are responsible for erectile rigidity. MUSE relies on the medication being locally absorbed by the spongy body and then diffusing into the adjacent cavernous bodies.

Why did Willie Sutton rob banks?  Because that’s where the money is.  When it comes to erections, the money is the erectile chambers. Because MUSE relies on absorption via the urethra and surrounding spongy body, the dosage required is significantly higher than when the medication is injected directly into the erectile chambers (penile injection therapy).  A 1000 microgram pellet may be needed in the urethra as opposed to only 10 micrograms when injected into the erectile chamber, indicative of the efficiency of injecting the medication directly into the erectile chamber as opposed to the inefficiency of relying on absorption from the spongy body.

An applicator is used to place and deploy the pellet within the urethra. The pellet is inserted after urinating, which functions to lubricate the urethra and ease the administration. The pellet dissolves in the small amount of urine remaining in the urethra after urination.  Side effects include pain during insertion, urethral burning, aching in the penis, testicles, perineum and legs, redness of the penis and minor urethral bleeding or spotting.

MUSE applicator with the MUSE pellet contained within

As an alternative to the branded product, some pharmacies–including Miller’s Pharmacy in Wyckoff, New Jersey– compound Alprostadil gel in a variety of dosages that can be injected into the urethra via a syringe as an alternative to the MUSE pellets.

IMHO:  Although urethral vasodilator therapy sounds reasonable in theory, in practice, administration is uncomfortable and the product does not work particularly well.  Although initially promising when first made available, experience has shown that most men do not find MUSE to be a successful means of restoring erections. On the other hand, penile injection therapy is another story entirely.


In 1982, French vascular surgeon Dr. R. Virag discovered the effect of the anti-spasmodic medication papaverine that is used to relax and expand blood vessels. When he mistakenly infused this drug into the penis, thinking he was administering saline, his patient immediately developed an erection and Dr. Virag realized that a new treatment for ED was possible.

At the 1983 American Urological Association meeting in Las Vegas an event occurred that forevermore changed the treatment of ED. In a huge conference hall attended by a large audience of urologists, a British physiologist named G. Brindley appeared from behind the podium and dropped his trousers, unveiling his erect penis. Minutes before, he had injected a vasodilator medication 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 developments have had the dramatic effect that Brindley’s demonstration had, supporting the principle that an erection is caused by smooth muscle relaxation within the penile erectile chambers.

Penile injections of vasodilator drugs are beneficial for a wide range of medical conditions that cause ED.  Vasodilator drugs injected directly into the penile erectile chambers bypass psychological, neurological and hormonal factors and act locally on the erectile tissues, causing blood to pour into the erectile chambers, inducing a rigid erection on demand. These injectable medications uniquely initiate an erection without sexual stimulation, as opposed to the oral ED medications that require sexual stimulation to work effectively.

A tiny needle is used to inject the medication directly into one of the paired penile erectile chambers on one side of the penis. An erection usually occurs within 5-30 minutes and lasts for a variable amount of time, depending on the dosage used. An injection-induced erection does not interfere with one’s ability to ejaculate or experience a climax. The erection will persist even after ejaculation has occurred, until the medication is out of the system.

Prostaglandin E1, a.k.a. alprostadil (Caverject, Edex) is a commonly prescribed vasodilator. Bimix consists of a combination of two vasodilators: papaverine and phentolamine. Trimix is a mixture of three vasodilator drugs in combination: prostaglandin E1, papaverine and phentolamine. Quadramix consists of four medications, Trimix with atropine added.  The use of combined medications increases the success rates of injection therapy.

Patients interested in penile injection therapy are taught the procedure during a urological office visit, at which time a test dose is administered. Although not a difficult technique to learn, it does require some dexterity. With practice and experience, one can become skilled and adept.  After learning the technique, the medication can be self-administered on demand. It often requires some trial and error to get the dosage calibrated so that the erection lasts an appropriate amount of time, in accordance with individual desires.

Side effects include possible pain, bleeding, bruising, scarring and prolonged erections. The most common side effect is a dull ache that is usually mild and tolerable. 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 may occur. An erection that lasts for more than four hours is a potentially serious issue that needs to be addressed.  If this happens, the following may prove helpful: increasing physical activity, e.g., running up a few flights of stairs to promote a “steal” of blood from the genitals to the muscles; applying an icepack to the penis; and pseudoephedrine (Sudafed) 30-60 mg. If the erection fails to subside, it will require the injection of a medication to reverse the effects of the vasodilator drug.

Sadly, there are some unscrupulous medical groups who prey on unsuspecting and vulnerable ED patients, offering injection therapy without discussion of alternative treatments and charging patients exorbitant fees for medications such as Trimix.

The reality is that medications such as Trimix can be obtained at reputable compounding pharmacies–such as Miller’s Pharmacy in Wyckoff, New Jersey– via prescription from your urologist 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, massage the penis to promote some penile blood flow and filling. The injection will be easier with a fuller penis.
  • Avoid superficial veins when doing the injection.
  • Only one side needs to be injected even though there are two erection chambers, since they communicate.
  • Hold pressure on the injection site for several minutes after the injection to avoid bleeding and bruising.
  • Vary the injection site on the side that you are using to avoid scarring.
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 (urethra). 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 (urethra).
  2. Use an alcohol swab to cleanse the base of the penis in order to prevent infections and then set aside the swab.
  3. Holding the 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 voilà, the rest is up to you!

Penile injection therapy can be a highly effective technique for men with ED following treatment of prostate cancer.  Not only does it permit achievement of a rigid erection effective for sexual intercourse, but it also helps rehabilitate the penis to maintain blood flow and tissue integrity that can be compromised in the absence of erections. 

Bottom Line:  Urethral suppository and penile injection therapy are “third line” means of managing ED.  Injection therapy is far superior to the suppositories in terms of achieving a rigid and durable erection.  Although the concept of “needle in penis” is daunting, the truth of the matter is that many men find that “a small prick for a larger one” is well worth the effort.

Wishing you the best of health,

2014-04-23 20:16:29

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Dr. Andrew Siegel is a physician and urological surgeon who is board-certified in urology as well as in female pelvic medicine and reconstructive surgery.  He is an Assistant Clinical Professor of Surgery at the Rutgers-New Jersey Medical School and is a Castle Connolly Top Doctor New York Metro Area,Inside Jersey Top Doctor and Inside Jersey Top Doctor for Women’s Health. His mission is to “bridge the gap” between the public and the medical community. He is a urologist at New Jersey Urology, the largest urology practice in the United States.  Today’s entry is excerpted from his latest book, Prostate Cancer 20/20: A Practical Guide to Understanding Management Options for Patients and Their Families. 

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Video trailer for Prostate Cancer 20/20

Preview of Prostate Cancer 20/20

Andrew Siegel MD Amazon author page

PROSTATE CANCER 20/20: A Practical Guide to Understanding Management Options for Patients and Their Families is now on sale at Audible, iTunes and Amazon as an audiobook read by the author (just over 6 hours). 

Dr. Siegel’s other books:

FINDING YOUR OWN FOUNTAIN OF YOUTH: The Essential Guide to Maximizing Health, Wellness, Fitness and Longevity

PROMISCUOUS EATING— Understanding and Ending Our Self-Destructive Relationship with Food

MALE PELVIC FITNESS: Optimizing Sexual and Urinary Health

THE KEGEL FIX: Recharging Female Pelvic, Sexual, and Urinary Health


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2 Responses to “Vasodilators to Manage Erectile Dysfunction”

  1. Anna Sandor Says:

    Ronald Virag (born December 7, 1938. In Metz, France), is a French cardiovascular surgeon, specialized in andrology (the medicine of masculine health). Inventor of the first medical treatment for impotence, andrology he designed many of the modern techniques of diagnosis and treatments for erectile dysfunction; and also a preventive program for the harmful effects of ageing in the cardiovascular, hormonal, sexual, urologic and nutritional areas. He is the author of several publications, scientific and popularization books.

    Biography Edit

    He was born in Metz, in 1938, from Hungarian parents who became French citizens before his birth. His father is a former professional soccer player, known as Edmond Weiskopf (1911–1996). After his school and college in the Ecole des Roches and Lycée Janson de Sailly, in Paris, he enters the Faculty of Sciences, then Medicine, of Paris. He was received as intern, subsequently as resident in Parisian Assistance Publique Hospitals. Afterwards, he is appointed Chief Resident at the Faculty and specializes in cardiovascular surgery. He creates several cardiovascular surgery units in private institutions before taking an interest in male sexual dysfunction caused by vascular diseases. He develops specific techniques to explore penile hemodynamics and designs various original surgical interventions, such as the penis dorsal vein arterialization which is named after him. In 1982, he discovers, almost by chance that an old medication, papaverine injected directly into the penis is able to provoke a long lasting erection Thus, he develops the technique of intracavernous injection used worldwide since 1983 to treat erectile dysfunction. He was appointed as a consultant at Harvard Medical School. He also teaches within the different structures of French and foreign medical societies. He is a permanent member of the French National Academy of Surgery.[1]

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