• Erectile dysfunction therapy

Papaverine (pa-PAV-er-een) belongs to the group of medicines called vasodilators. Vasodilators cause blood vessels to expand, thereby increasing blood flow. Papaverine is used to produce erections in some men with erectile dysfunction. When papaverine is injected into the penis (intracavernosal), it increases blood flow to the penis, which results in an erection.

Papaverine injection should not be used as a sexual aid by men who do not have erectile dysfunction. If the medicine is not used properly, permanent damage to the penis and loss of the ability to have erections could result.

Papaverine is available only with your doctor's prescription, in the following dosage form:

Parenteral
• Injection (U.S. and Canada)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For papaverine, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to papaverine. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Older adults—Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. Although there is no specific information comparing the use of papaverine for erectile dysfunction in the elderly with use in other age groups, this medicine is not expected to cause different side effects or problems in older people than it does in younger adults.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your health care professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.

• Bleeding problems—These conditions increase the risk of bleeding at the place of injection

• Liver disease—Papaverine can cause liver damage when it is given in ways that allow it to get into the bloodstream (by mouth or by injection into a muscle, a vein, or an artery); when papaverine is given by intracavernosal injection, liver damage is much less likely because the medicine enters the bloodstream very slowly

• Priapism (history of) or
• Sickle cell disease—Patients with these conditions have an increased risk of priapism (erection lasting longer than 4 hours) while using papaverine

To give papaverine injection:

• Cleanse the injection site with alcohol. Using a sterile needle, inject the medicine slowly and directly into the base of the penis as instructed by your doctor. Papaverine should not be injected just under the skin. The injection is usually not painful, although you may feel some tingling in the tip of your penis. If the injection is very painful or you notice bruising or swelling at the place of injection, that means you have been injecting the medicine under the skin. Stop, withdraw the needle, and reposition it properly before continuing with the injection.
• After you have completed the injection, put pressure on the place of injection to prevent bruising. Then massage your penis as instructed by your doctor. This helps the medicine spread to all parts of the penis, so that it will work better.

This medicine usually begins to work in about 10 minutes. You should attempt intercourse within 2 hours after injecting the medicine.

Dosing—

The dose of papaverine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of papaverine. If your dose is different, do not change it unless your doctor tells you to do so.

• For injection dosage form:
  • For the treatment of erectile dysfunction:
    • Adults—30 to 60 milligrams (mg) injected very slowly into the area of your penis as directed by your doctor. Allow one or two minutes to completely inject the dose. Do not inject more than one dose in a day. Also, do not use this medicine more than two days in a row or more than three times a week.

Storage—

To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Keep the medicine from freezing.

Use papaverine injection exactly as directed by your doctor . Do not use more of it and do not use it more often than ordered. If too much is used, the erection may become so strong that it lasts too long and does not reverse when it should. This condition is called priapism, and it can be very dangerous. If the effect is not reversed, the blood supply to the penis may be cut off and permanent damage may occur.

Contact your doctor immediately if the erection lasts for longer than 4 hours or if it becomes painful. This may be a sign of priapism and must be treated right away to prevent permanent damage.

If you notice bleeding at the site when you inject papaverine, put pressure on the spot until the bleeding stops. If it doesn't stop, check with your doctor.

It is important for you to examine your penis regularly. Check with your doctor if you find a lump where the medicine has been injected or if you notice that your penis is becoming curved. These may be signs that unwanted tissue is growing (called fibrosis), which should be seen by your doctor.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if the following side effect occurs:

• Rare
  • Erection continuing for more than 4 hours, or painful erection  
  
  

Check with your doctor as soon as possible if the following side effects occur:

• Rare
  • Dizziness;  lumps in the penis 
  
  

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

• Less common or rare
  • Bruising or bleeding at place of injection;  burning (mild) along penis;  difficulty in ejaculating ;  swelling at place of injection 
  
  

Papaverine injected into the penis may cause tingling at the tip of the penis. This is no cause for concern.

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although this use is not included in product labeling, papaverine is used in certain patients with the following medical conditions:

• Low doses of a three-drug combination of papaverine, phentolamine, and alprostadil as an injection may be used to treat erectile dysfunction.