Injection Therapy for Erections

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The first medicine used for this purpose was Papaverine, a potent vasodilator (which makes arteries dilate).  Papaverine, unfortunately, can cause priapism, or a dangerous and painful erection that will not go down, with some regularity.  Thus, other medicines are also used today for this purpose, often as a mixture of medicines to utilize each drug’s benefits and limit its side effects.

Prostaglandin had once been sold as a stand-alone injection for ED called Caverject or Edex.  Its main drawback is penile pain.  A third medicine that causes potent penile vasodilation is phentolamine.  When all three are mixed, it is called Tri-Mix.  Others can be added, such as Atropine, to produce Quad-Mix.  The proportions of these medicines can be changed to lessen one side effect or another until a helpful solution is found, but almost all patients are started on a standard solution of Tri-Mix.

Injection therapy should be taught to the patient, which our nurse practitioner most commonly performs at either office location. The medicine would have been prescribed from a specific compounding pharmacy during a previous visit, and that medicine with alcohol swabs and syringes would have been shipped to the patient at home. During the teaching visit, the patient brings one vial of their medicine to the office with their own needles and alcohol. The needle and syringe used are identical to what a person with diabetes would use to inject insulin. At that visit, the patient is taught how to draw up the medicine, use the syringe and needle and communicate about their dose using the numbers on the syringe only without units.  The patient is also instructed on how to hold the penis properly to allow for the easiest administration and injection. Results are immediate with injections and generally work far more reliably and completely than any other modality. Shots also work faster than pills and can be considered more spontaneous in some ways. However, injections require motivation. All patients are apprehensive about giving themselves a shot, but the almost unanimous reaction of the patient is that it is far easier to do than they imagined, and the patient gets used to it over time just as a person with diabetes does. We have found that the teaching visit goes far more smoothly and that the patient is more likely to succeed with injections at home if they come to the teaching visit having already read an extensive tutorial on giving themselves these shots.  Below are detailed instructions, a diagram, and a photo that should prepare patients extensively for their teaching visit in the office.

ED Questions answered bannerThe medicine will come in several small vials to be kept frozen when not in use.  The foil is removed, the top is wiped with alcohol, and the needle is inserted into the bottle.  It is best to pull the syringe’s plunger back to the intended dose number and then insert the needle into the bottle.  That amount of air is injected into the vial, and with the vial upside down, the medicine is drawn back into the syringe.  Usually, one pulls more than is needed into the syringe, then depresses the plunger with the needle still in the vial until the desired number or dose is reached.  The needle is then withdrawn, and the needle and syringe are set aside.  The patient is now ready to inject himself.

Proper Way to Hold the Syringe

The proper way to hold the syringe is with the thumb on the platform of the syringe.  The syringe is held as one would hold a cigarette.  Note the numbers used to determine and describe the dose.

Although patients usually see the actual injection as the key here to success and certainly the focal point of their anxiety, the most important things for the patient to master is how to hold their penis properly and where to inject.  Often the patient will hold their penis at first only to then focus only on their injection hand and then fail to continue holding their penis in an advantageous way.  The more firmly the penis is pulled away from the body, the easier the needle will be inserted into the penis.  So, maintain focus on the non-dominant holding hand perhaps even more so during the injection.  The figure below illustrates these concepts clearly.  The penis is held with the non-dominant hand with the index and middle finger under the urethral meatus, and the pad of the thumb over the top of the glans or head.  It is vital to hold the head of the penis without touching the penile skin at all, then to pull the penis straight out from the body as firmly as possible.  This allows the needle to slide in with ease.  Then, with the dominant hand, the patient holds the syringe like a cigarette between the index and third finger, with the thumb holding the syringe at the level spot below the plunger.  (See photo) Then, the injection is to be done anywhere along the shaft at what would be 10 or 2 o’clock when viewing the penis straight on from the head.  The shot must be perpendicular to 10 or 2 o’clock as shown in the drawing, and the needle must not slip down towards the urethra.  The patient touches the skin with the needle, engages the skin and then pushes the needle all the way in.  Only the skin senses pain here, so the depth of the needle does not dictate the pain at all.  Then, the medicine is injected, after which the needle is removed quickly, and pressure is applied with the alcohol swab for perhaps 10 seconds to avoid bruising.  Patients will be asked to attempt to get an erection, and the results are then evaluated.  The response in the office will dictate what the starting dose at home should be.

Proper Method to Hold the Penis

Drawing illustrating the proper method to hold the penis for an injection.  Note that only the glans is held without touching the penile skin.  Injection zones are along either side of the shaft at 10 or 2 o’clock on a clock, as pictured.












A very low dose will be used in the office based on existing erectile function, and then Dr. Engel will advise a starting dose at home.  The dose should be increased by small increments after the starting dose, often as low as two on the syringe but more typically 4 or 5.  Finding the right amount in this incremental way should avoid priapism and therefore is mandatory.  Of course, this means that the first several attempts often will not result in intercourse.  Patients should expect that.  However, the dose should be increased each time until a dose that produces a firm erection adequate for satisfactory intercourse while not lasting over an hour is achieved.  Patients should not think that they should stop increasing the dose at any point if a good erection does not occur.  Occasionally, patients need a high dose, such as 80 or more.  In these cases, the prescription can be adjusted to a higher-strength solution at the next office visit.

Click an Image Below to Download the Injection Guide

Risks and Considerations of Injection Therapy

Injections are safe, as a negligible amount of medicine enters the patient’s bloodstream.  The main thing to avoid is priapism, which happens very rarely if starting with a low dose as instructed by us.  If an erection lasts beyond three hours, Sudafed should be taken immediately, and ice should be applied to the penis.  This really should be done on the way to an emergency room with the hope that the penis will get soft on the way in.  An erection lasting four hours will usually be quite painful and requires an immediate visit to an emergency room – please dial 911 or go to your nearest or favorite emergency room and ensure that Dr. Engel or Dr. Tobon are contacted to take part in your care. As a reminder, USW physicians have privileges at Reston Hospital Center, Holy Cross Hospital Silver Spring, and Holy Cross Hospital Germantown, but patients are strongly encouraged to go to their local emergency room if priapism occurs.  Patients are told to alternate the sides of the injection if possible or to avoid injecting in the same spot on either side repeatedly to reduce the risk of scarring, which may occur.  Patients are to inject at most every other day, and very importantly, to never give a “booster” injection if a good erection is not achieved with one injection, which is one of the most common reasons for priapism.

In short, injection therapy should be the next step if pills fail.  They are not rare, not “weird,” and are certainly used with far more regularity than the public knows.  They are a great solution, and all patients are strongly encouraged to try them before giving up on an active sex life.  We will be more than happy to help you.


Urologic Surgeons of Washington is a proud member of Privia Medical Group. The best doctors in our community have joined together to form Privia Medical Group (PMG), a multi-specialty, high-performance medical group that puts patients first. Our physicians are united by the mission of providing better, more coordinated care for their patients.

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