Penile Injection Therapy

This information will help you learn to inject medication into your penis. This is called penile injection therapy. Penile injections can help you achieve an erection if you have erectile dysfunction (ED).

‌​ Read this resource carefully before starting injection therapy. If you don’t follow the instructions in this resource, your doctor or APP may stop prescribing your penile injection medications and supplies.

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About Penile Injection Therapy

The tissue that causes you to get an erection (erectile tissue) is a muscle. Going long periods of time without an erection is unhealthy for erectile tissue and may damage it.

We believe that having erections keeps erectile tissue healthy. A penile injection helps you have an erection. It works best if it’s given about 5 to 15 minutes before you want an erection.

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Giving Yourself the Injection

Your advanced practice provider (APP) will review the instructions below with you. Generally, the training for the injections takes 2 office visits. Please be aware that each visit may take up to 1 hour, so you should plan your schedule on the day of your appointment.

Use this resource to help you the first few times you inject on your own.

Do not take the following medications within 18 hours of injecting (before or after):

  • Sildenafil (Viagra®) - 20 mg to 100 mg
  • Vardenafil (Levitra®) - 10 mg to 20 mg
  • Avanafil (Stendra®) - 50 mg to 200 mg

If you take tadalafil (Cialis®) 10 mg or 20 mg, do not inject within 72 hours (3 days) of taking the medication.

If you are using tadalafil (Cialis) 5 mg daily, ask your APP how you should use this medication along with your injections.


The 3 most commonly used medications for injection therapy are Trimix, Bimix, and Papaverine. Most men begin injection therapy with Trimix, which is a mixture of 3 ingredients: alprostadil, phentolamine, and papaverine. These ingredients work by relaxing the smooth muscle and opening the blood vessels in your penis, causing an erection. Your APP will decide whether Trimix or a different medication is best for you.

Storing your medication

The alprostadil in Trimix can weaken over time, so Trimix should be stored in the refrigerator and away from light. This can keep the medication good for a few additional months. If you’re using Bimix or papaverine, you don’t need to keep the medication in your refrigerator because these medications don’t contain alprostadil.

Don’t use the medication if:

  • It has particles or is cloudy.
  • The rubber stopper comes off of the vial.

After your second training visit, your medication will be delivered directly to your home from the compounding pharmacy (specialized pharmacy). Call the compounding pharmacy to make arrangements for billing and shipping. This will limit delays in delivery.

Call your APP when you need a new prescription.

Preparing the injection

  1. Prepare a clean surface for your supplies.
  2. Gather your supplies:
    • 1 medication vial
    • 1 syringe (one-time use only)
    • 2 alcohol wipes
    • Sharps container. You can use an empty detergent or bleach bottle with a cap, or a metal coffee can with a plastic top.
  3. Wash your hands well with soap and water.

Drawing up the medication from the vial

  1. If you’re using the medication for the first time, take the cap off. Throw the cap away. Open an alcohol wipe and wipe the rubber stopper on the top of the vial. You must always wipe the rubber stopper with alcohol before you insert the needle. This will kill any bacteria on the rubber stopper.
  2. Take the syringe out of its package. Remove the cap from the needle. Be very careful not to let anything touch the needle. If anything touches the needle, you must throw the entire syringe away in the sharps container and use a new one. This is because it will no longer be sterile.
  3. First, holding the syringe upright so the needle faces the sky, pull the plunger of the syringe back past the dose you were told to inject. Next, push the plunger back up until the top of the plunger (the thin black line closest to the needle) is at the dose you were told to inject.
  4. Turn the syringe downward so the needle is facing the floor. Hold the syringe in your hand like you hold a pen or dart. Hold the syringe close to the needle with your thumb, index (first) and middle (second) fingers. This will keep the needle from bending as you insert it into the rubber stopper. Support the medication vial with your other hand.
  5. Holding the vial upright and the syringe downward, insert the needle through the circle in the center of the rubber stopper. Push the plunger down to inject the air into the vial (see Figure 1). You do this because the vial is pressurized. You must replace the amount of medication you remove from the vial with air.
  6. Turn the vial and syringe upside down (see Figure 2). Hold the syringe with the hand you use to write with and the vial with your other hand. Don’t let go of the vial, or the needle will bend. Make sure the tip of the needle is in the medication. Rotate the syringe so you’re looking at the numbers and lines on the syringe.
    Figure 1. Injecting air into the vial

    Figure 1. Injecting air into the vial

    Figure 2. Withdrawing the medication

    Figure 2. Withdrawing the medication

  7. Pull the plunger down past your prescribed dose. This will help remove any air bubbles. Slowly push the plunger back up to your prescribed dose. Check the amount of medication in the syringe to make sure it’s the correct dose.
  8. Check for air bubbles in the syringe. If you see any air bubbles, pull more medication into the syringe. They will go to the top, towards the needle. Slowly push the air bubbles and the extra medication back into the vial. Look at the syringe again to make sure that you have the right amount of medication.
  9. When you have the correct amount, pull the needle out of the vial. Place the cap back on the syringe without touching or bending the needle. If you touch or bend the needle, you will need to throw away the syringe and start at step 2. When you place the cap back on the syringe, make sure you don’t push the plunger by accident. This will push the medication into the cap and result in the wrong amount when it’s time to inject yourself.
  10. If you’re using Trimix, put the medication vial back into the refrigerator. If you’re using Bimix or Papaverine, you don’t need to keep your medication in the refrigerator.

Choosing an injection site

You must inject the medication into a specific area of your penis. This is so you don’t inject into a nerve or blood vessel.

Imagine that your penis is divided in 3 parts. You will give the injection in the middle third of your penis at the 10 o’clock (left side) or the 2 o’clock (right side) position (see Figure 3).

Figure 3. Choosing an injection site

Figure 3. Choosing an injection site

To prevent trauma to your penile tissue, always change sides of your penis each time you inject the medication (right side, then left side). Keep a record each time so you don’t forget. Don’t inject into any vein you can see or feel because it could cause a large bruise on your penis. Don’t inject straight down on the top or the bottom of your penis.


Injecting the medication

  1. Grasp the head of your penis, not the skin. This will allow your penis to be more fully stretched. It’s easiest to inject if your penis is pulled straight out in front of you. If you aren’t circumcised, pull your foreskin back before grasping the head of your penis. This will prevent the needle from going between the skin and erectile tissue. For your injection to work, the medication needs to go into the erectile tissue.
  2. Locate the area to be injected (the middle third of your penis). Wipe it with an alcohol wipe. Let go of the head of your penis and pick up the syringe with 2 hands.
  3. Remove the cap covering the needle. Look at the syringe to make sure the dose is correct and you haven’t pushed any medication out by accident.
  4. Hold the syringe between your thumb, index and middle fingers like a pen or a dart. The needle should be facing the floor. Don’t place your index finger or thumb on the plunger.
  5. Once again, grasp the head of your penis and pull it straight out. Keep pulling on your penis from the time the needle goes into your penis until it comes out. Don’t twist your penis, since this could lead to injecting the wrong area.
  6. Touch the needle to your skin and quickly slide it into the shaft of your penis. Remember to avoid any veins. Make sure to insert the needle at a slight angle (either the 10 o’clock or 2 o’clock position, as shown in Figure 3).
  7. Move your finger so that your index finger or thumb can push in the plunger.
  8. Quickly push down on the plunger to inject the medication into the shaft of your penis. Be careful not to pull the syringe out as you’re injecting the medication.
  9. Once you have injected all of the medication, quickly pull the needle out of your penis. Pull it straight out. Don’t use a twisting or jerking motion, because this may cause bruising. Apply pressure at the injection site for 2 to 3 minutes with your thumb on the injection site and your index finger on the opposite side of your penis. If you’re taking a blood thinner or aspirin, hold the pressure for 5 minutes. This will help to decrease any bleeding or bruising.
  10. Place the syringe in the sharps container. You don’t need to recap it.
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Erection Scale

It usually takes a few injections to find the right dose for an erection firm enough to have sex. It’s important that you follow the treatment plan that your APP gave you. Don’t adjust your own dosing. If you’re adjusting your own medication dosing, the office will no longer be able to prescribe your medication.

Please use the grading scale below to rate your level of hardness after injecting. Call your APP and tell them your responses and whether you’re getting the results you want. Your APP will tell you which dose to try next based on your response.

Reporting your injections

Please make sure to include the information below in your injection reports.

For your first injection: inject ___________ units of ____________________________ while you’re at home.

Use the erection scale above and record your response below.

  • My erection was a _________ on a scale of 0 to 10.
  • My erection lasted _________ minutes/hours until it became a 5 on the erection scale.

Call your APP after each injection to report your response. Keep calling your APP after each injection until we find the right dose for you. Phone number:________________________________________

Do not change your dose without speaking with your APP.

Do not give yourself your next injection until you have reported the result of your last injection.

Important Points

  • Don’t take more medication than the dose prescribed.
  • Don’t change the dose without speaking to your APP.
  • Don’t take more than 1 injection in 24 hours.
  • Don’t give yourself another injection if the medication doesn’t work. Speak with your APP if you aren’t getting the effects you want.
  • Your partner shouldn’t inject you if they did not inject you at your training session.
  • You can inject up to 3 times a week as long as there are 24 hours between each injection.
  • If you’re currently receiving chemotherapy for cancer, ask your oncologist (cancer doctor) when you can safely inject.
  • Don’t take any other medication for ED without speaking to your APP.
  • Do not go to sleep until your erection is bendable.
  • Do not take the following medications within 18 hours of an injection (before or after):
    Medication Dose
    Sildenafil (Viagra) 20 mg to 100 mg
    Vardenafil (Levitra) 10 mg to 20 mg
    Avanafil (Stendra) 50 mg to 200 mg
  • Do not inject within 72 hours (3 days) of taking tadalafil (Cialis) 10 mg or 20 mg.
  • If you’re using tadalafil (Cialis) 5 mg daily, ask your APP how you should use this medication along with your injections.
  • Tell your APP all of the medications you’re taking, especially if you’re taking one of the following:
    • Medication for depression, or classified as an MAO inhibitor such as phenelzine (Nardil®)
    • A sleep aid, such as trazodone (Oleptro ER®)
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Your APP will order your supplies for you from a compounding pharmacy. Your supplies will include:

  • 1 vial (500 units) of ______________________ medication
  • 30 syringes (29 gauge, ½ inch)
  • 24 pseudoephedrine HCl (Sudafed®) 30 mg tablets

You will also need to buy alcohol pads from your local pharmacy.

Your injection medication can’t be ordered from your local retail pharmacy (such as CVS, Rite Aid, Duane Reade, or Costco). They will be ordered from a specialty compounding pharmacy approved by MSK.

Please call your APP when your supplies run low. They will order more supplies for you and will let you know if refills are included. You’ll need to provide an injection report with each refill request. If refills are included, you can contact the compounding pharmacy directly to set up your billing and shipping.

Pseudoephedrine HCl (Sudafed)

Sometimes, penile injections can cause priapism (an erection that lasts too long). If you have priapism, taking pseudoephedrine HCl can help. Read the instructions in the “Treating Priapism (An Erection That Lasts Too Long)” section for more information.

If you want to buy the pseudoephedrine HCl at your local pharmacy, you don’t need a prescription, but the boxes are kept behind the pharmacy counter. Take the pseudoephedrine HCl card that’s hanging on the shelf to the pharmacist (see Figure 4). You will have to show a photo ID before the pharmacist gives you the box to purchase.

Figure 4. Pseudoephedrine HCl

Figure 4. Pseudoephedrine HCl

Make sure to have pseudoephedrine HCl with you as long as you’re using the penile injections.

If you have problems with your heart, talk with your cardiologist about whether it’s safe for you to take pseudoephedrine HCl.

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Treating Priapism (An Erection That Lasts Too Long)

Priapism is an erection that lasts too long. Priapism can develop without sexual stimulation and doesn’t go away after orgasm. There is a risk of having priapism after penile injection therapy.

When you have a full erection, no fresh blood flows into your penis. This means that your penis isn’t getting oxygen, which can damage the tissue and lead to permanent ED.

If you develop priapism

  • If you have an erection at penetration hardness (a 6 or higher on the erection hardness scale) that lasts 2 hours, take 4 (30 mg) tablets of pseudoephedrine HCl (Sudafed). Don’t take extended-release or long-acting tablets, such as Sudafed 12 hour. Ask your pharmacist or APP if you have any questions. The pseudoephedrine HCl will be shipped by the compounding pharmacy along with the vial of medication and syringes, or you can buy it at your local pharmacy. For more information, read the “Pseudoephedrine HCl (Sudafed)” section above.
    • If your erection becomes less than penetration hardness within an hour of taking pseudoephedrine HCl, call your doctor’s office the next day to speak with your APP. You should not use your penile injections again until speaking to your APP. Your APP will make changes to your penile injection therapy medication dose.
  • If you have an erection that lasts 3 hours (you still have an erection 1 hour after taking the pseudoephedrine HCl), call your APP and plan to go to MSK’s Urgent Care Center or your local emergency room.
    • Monday through Friday between 9:00 am and 5:00 pm, call your APP.
      • Phone number: __________________________________________
    • Between 5:00 pm and 9:00 am, during the weekend, and on holidays, call 212-639-2000 and ask to speak to the urologist on call.
    • Go to MSK’s Urgent Care Center at Memorial Hospital (1275 York Avenue, between East 67th and East 68th Streets) if you’re less than 30 minutes away. Your APP will call the Urgent Care Center so they know to expect you. Your APP will give you more instructions during your call.
    • Go to your local emergency room if you’re more than 30 minutes away from MSK’s Urgent Care Center. Your APP will give you more instructions during your call.
  • If you have an erection that lasts 3 hours and you haven’t talked to your APP, this is a medical emergency. You should treat it with the same urgency as a heart attack. Erections lasting longer than 4 hours can cause permanent damage to your erection tissue.
    • Go to MSK’s Urgent Care Center if you’re less than 30 minutes away. Ask the guard at the entrance to the hospital how to get there.
    • Go to your local emergency room if you’re more than 30 minutes away from MSK’s Urgent Care Center.
    • Tell the staff at the Urgent Care Center or emergency room that you’ve had an erection for 4 hours. A doctor or nurse should see you immediately. If you aren’t treated quickly, it’s possible that you will end up with permanent ED.
    • Give the doctor or nurse the priapism card that was given to you to carry in your wallet. You can also have the doctor or nurse call us at the numbers listed above.
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After Pelvic Surgery for Prostate or Bladder Cancer

If you have had pelvic surgery for prostate or bladder cancer within the past year, your doctor may have told you to take a low dose of sildenafil (Viagra), vardenafil (Levitra), avanafil (Stendra), or tadalafil (Cialis) every night, except on days or nights you plan to inject. This improves the chance that your erectile function will return. It may also help save erectile tissue.

  • Do not take the following medications within 18 hours of an injection (before or after):
    Medication Dose
    Sildenafil (Viagra) 20 mg to 100 mg
    Vardenafil (Levitra) 10 mg to 20 mg
    Avanafil (Stendra) 50 mg to 200 mg
  • Do not inject within 72 hours (3 days) of taking tadalafil (Cialis) 10 mg or 20 mg.
  • If you’re using tadalafil (Cialis) 5 mg daily, ask your APP how you should use this medication along with your injections.

Your response to oral ED medications may improve over the first 18 to 24 months after surgery. Try taking a full dose once a month. A full dose is one of the following:

  • 100 mg of sildenafil (Viagra) taken on an empty stomach (2 hours before or 2 hours after a meal).
  • 20 mg of vardenafil (Levitra) taken on an empty stomach.
  • 200 mg of avanafil (Stendra) taken with or without food.
  • 20 mg of tadalafil (Cialis) taken with or without food.

Record your response. To achieve the best response, you must be:

  • Relaxed
  • Sexually aroused, either from contact with a partner or from self-stimulation
  • Not tired
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Traveling with Your Medication

Speak with your APP about how to travel with your injection medication. They can give you a letter explaining your treatment, if needed. If you need a letter, be sure to ask for it before your travel dates.

To safely travel with your medication:

· You must travel with Sudafed.

· You must be within an hour away from a hospital.

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Storing and Disposing of Your Home Medical Sharps

For information about storing and disposing of your home medical sharps, read our resource How to Store and Dispose of Your Home Medical Sharps.

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