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Overview: Alprostadil is used to diagnose and treat erectile dysfunction (ED). The most common side effect with alprostadil is penis pain. Serious side effects are rare but can include an unwanted erection that may last a long time, be painful, and that may occur without sexual arousal. Stop using alprostadil and get emergency help if you have an erection that is painful or that lasts more than four hours.

Uses

What is alprostadil used for?

Alprostadil is commonly used to diagnose and treat erectile dysfunction, a condition where you have trouble getting or keeping an erection.

Alprostadil may also be used for other conditions as determined by your healthcare provider.

How does alprostadil work (mechanism of action)?

Alprostadil relaxes the muscle in the penis and widens the blood vessels. This allows more blood to flow in and fill the tissue. The extra blood gets trapped, causing an erection.

How is alprostadil supplied (dosage forms)?

Brand and other names

  • Caverject
  • Caverject Impulse
  • Edex

Dosage forms and strengths

  • 10 mcg, 20 mcg, 40 mcg for injection

How should I store alprostadil?

Before mixing, alprostadil should be stored at room temperature around 77 F (25 C) and may be exposed to temperatures of 59 F to 86 F (15 C to 30 C) for shorter periods of time, such as during travel. Store it in a cool, dry place.

After mixing, some alprostadil products can be stored for up to 24 hours. Other alprostadil products should be used right after mixing them. Follow the instructions provided with your medicine for how to mix and store your alprostadil product. If you have questions, ask your healthcare provider or pharmacist. 

Side Effects

What are the most common side effects of alprostadil?

The most common side effect of alprostadil is pain in your penis. Tell your healthcare provider if you have penis pain that bothers you.

There may be other side effects of alprostadil that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of alprostadil?

While less common, the most serious side effects of alprostadil are described below, along with what to do if they happen.

Severe Allergic Reactions. Alprostadil may cause allergic reactions, which can be serious. Stop using alprostadil and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Painful, Prolonged Erection (Priapism). Alprostadil may cause an unwanted erection that may be persistent, painful, and that may occur without sexual arousal. Permanent damage to the penis may occur if priapism is not treated quickly. Stop using alprostadil and get emergency help if you have any of the following symptoms of priapism.

  • Erection lasting for more than four hours
  • Erection that is unrelated to sexual stimulation
  • Painful or tender penis

Penis Scar Tissue (Penile Fibrosis). Alprostadil may cause scar tissue, which can lead to an abnormal curve of your penis. Stop using alprostadil and tell your healthcare provider right away if you have any of the following signs of scar tissue.

  • New or worsening pain or tenderness in your penis
  • Swelling, redness, or hard lumps (nodules) in your penis
  • An unusual curve or bend in your penis 

Low Blood Pressure (Hypotension). Alprostadil may cause low blood pressure. If you feel faint or dizzy, lie down. Tell your healthcare provider right away if you have any of the following symptoms of low blood pressure.

  • Dizziness or feeling lightheaded
  • Feeling weak or tired
  • Fainting

Bleeding at Injection Site. Alprostadil may cause bleeding where you inject it into your penis. You may be at higher risk if you use a blood thinner medicine. If you bleed, apply pressure for five minutes using sterile gauze or an alcohol swab. Tell your healthcare provider right away if you have bleeding, bruising, or color changes of your penis.

Warnings & Precautions

Who should not use alprostadil?

Allergies to Ingredients. People who are allergic to any of the following should not use alprostadil.

  • Alprostadil
  • Caverject
  • Caverject Impulse
  • Edex
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific alprostadil products they stock.

Curved Penis. Alprostadil should not be used to treat erectile dysfunction if you have penile scar tissue (fibrosis), Peyronie's disease, or your penis is abnormally curved.

Blood Disorders. Alprostadil should not be used if you have any of the following blood disorders. 

Penile Implant. Alprostadil should not be used if you have an implant in your penis.

What should I know about alprostadil before using it?

Do not use alprostadil unless it has been prescribed to you by a healthcare provider. Use it as prescribed.

Do not share alprostadil with other people, even if they have the same condition as you. It may harm them. Do not share needles with another person. Always use a new needle for each injection.

Keep alprostadil out of the reach of children. Since this medicine may be stored in a refrigerator, take special care to keep it away from children who also use the refrigerator.

The first dose of alprostadil is usually given by a healthcare provider. You will be shown how to prepare and give the injection. Make sure that you understand and feel confident in the process before using it at home. Read and follow the “Instructions for Use” that come with your medicine. Ask your healthcare provider if you have any questions about how to use alprostadil.

This medicine is injected into the penis using a very thin needle. Follow your healthcare provider’s instructions to avoid bending or breaking the needle. If a needle bends, do not use it. If a needle breaks, remove it (if possible) and contact your healthcare provider right away.

Alprostadil should be thrown away in a sharps container to protect others from contact with the needle. Ask your healthcare provider if you have any questions about how to throw away alprostadil (and the supplies needed to use it). 

Sexual activity can put extra strain on your heart. This strain may not be safe for people with certain health problems, such as a recent heart attack. Talk to your healthcare provider to see if your heart is strong enough for sex. If you feel chest pain, dizziness, or nausea during sex, stop and contact your healthcare provider right away.

Alprostadil does not protect against sexually transmitted infections, including HIV. Talk with your healthcare provider about ways to reduce your infection risk during sex.

What should I tell my healthcare provider before using alprostadil?

Tell your healthcare provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if alprostadil is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your healthcare provider if you have any of the following.

  • An erection lasting longer than four hours
  • Low blood pressure
  • Bleeding problems
  • Heart problems, such as heart rhythm problem, chest pain, heart attack, or heart failure
  • Cavernosal venous leak, a condition where blood vessels in the penis are too weak or damaged to hold blood to maintain an erection

Other Medicines and Supplements. Alprostadil may interact with other medicines and supplements. Before using alprostadil, tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. People who can become pregnant are not usually prescribed alprostadil. Tell your healthcare provider if you are or plan to become pregnant.

Breastfeeding. People who can breastfeed are not usually prescribed alprostadil. Tell your healthcare provider if you are breastfeeding or plan to breastfeed.

Interactions

Does alprostadil interact with foods or drinks?

There are no known interactions between alprostadil and foods or drinks.

It is unknown if drinking alcohol will affect alprostadil.

Does alprostadil interact with other medicines (drug interactions)?

Always tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before starting alprostadil.

  • A blood thinner medicine, which is a medicine used to treat or prevent blood clots
  • A medicine injected into the penis

This may not be a complete list of medicines that can interact with alprostadil. Always check with your healthcare provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much alprostadil?

If you or someone else has used too much alprostadil, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of alprostadil?

Alprostadil is meant to be used only when needed. Use it as your healthcare provider recommends. Do not use double or extra doses.