Phentolamine (Injection)

Phentolamine given by injection makes blood vessels widen, which increases blood flow. When injected into the penis (intracavernosal), it boosts blood flow to the penis, leading to an erection.

This medicine should not be used as a sexual aid by men who do not have erectile dysfunction. If the medicine is not used correctly, it could cause permanent damage to the penis and loss of the ability to have erections.

Phentolamine may also be used to reverse the effects of an anesthetic medicine in soft tissues, like the lips and tongue. It can help quickly restore normal sensation and function in patients who have received local dental anesthesia.

Phentolamine is available only with your doctor's prescription.

Use the injection exactly as your doctor directs. Do not use more than prescribed and do not use it more often than instructed. Using too much can cause an erection that lasts too long and does not go away when it should. This condition is called priapism and can be very dangerous. If the effect does not reverse, the blood supply to the penis may be cut off, leading to permanent damage.

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

If you notice bleeding at the injection site, apply pressure to the area until the bleeding stops. If it does not stop, consult your doctor.

It is important for you to check your penis regularly. Speak with your doctor if you find a lump where the medicine was injected or if you notice that your penis is becoming curved. These could be signs of unwanted tissue growth (called fibrosis), which should be evaluated by your doctor.

In deciding to use a medicine, you and your doctor need to weigh the risks against the benefits. Here are some important points to consider for this medicine:

Allergies

Inform your doctor if you have ever had an unusual or allergic reaction to this medicine or any other medicines. Also, tell your healthcare professional about any other allergies you may have, like to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients closely.

Pediatric

Appropriate studies have not been done on how age affects the use of phentolamine for reversing soft-tissue anesthesia in children younger than 6 years. Its safety and effectiveness have not been established for this age group.

Geriatric

Many medicines have not been specifically studied in older adults. Therefore, it may be unclear whether they work the same way in older adults as they do in younger adults or if they cause different side effects or issues. Although there is no specific information about using phentolamine for erectile dysfunction in older people, it is not expected to cause different side effects or problems in older adults compared to younger adults.

Breast Feeding

There are no adequate studies in women to determine the risk to infants when using this medication while breastfeeding. Consider the potential benefits and risks before taking this medication during breastfeeding.

Interactions with Medicines

Some medicines should not be used together at all, while others may be used together even if there could be an interaction. In these cases, your doctor may need to adjust the dose, or take other precautions. It is very important for your healthcare professional to know if you are taking any of the medicines listed below while using this medicine. The following interactions are based on their potential significance and are not necessarily a complete list.

Using this medicine with any of the following medicines is generally not recommended, but may be necessary in some cases. If both medicines are prescribed, your doctor may adjust the dose or frequency of one or both medicines.

• Alfuzosin
• Asenapine
• Melphalan
• Silodosin
• Tadalafil
• Tamsulosin
• Vardenafil

Using this medicine with any of the following medicines may increase the risk of certain side effects, but using both may be the best treatment for you. If both are prescribed together, your doctor may alter the dose or frequency of one or both medicines.

• Acebutolol
• Alprenolol
• Atenolol
• Betaxolol
• Bevantolol
• Bisoprolol
• Bucindolol
• Carteolol
• Carvedilol
• Celiprolol
• Dilevalol
• Esmolol
• Labetalol
• Levobunolol
• Mepindolol
• Metipranolol
• Metoprolol
• Nadolol
• Nebivolol
• Oxprenolol
• Penbutolol
• Pindolol
• Propranolol
• Sotalol
• Talinolol
• Tertatolol
• Timolol

Interactions with Food/Tobacco/Alcohol

Some medicines should not be used around meal times or with certain foods due to possible interactions. Consuming alcohol or tobacco with certain medicines can also lead to interactions. Talk to your healthcare professional about using your medicine with food, alcohol, or tobacco.

Other Medical Problems

Having other medical issues may impact how you can use this medicine. Be sure to inform your doctor if you have any other medical conditions, especially:

• Bleeding problems—These conditions can increase the risk of bleeding at the injection site.

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

Along with its necessary effects, a medicine may cause some unwanted effects. Not all of these side effects may occur, but if they do, they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

Rare

• Dizziness
• Erection lasting more than 4 hours, or painful erection
• Lumps in the penis

Some 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. Your health care professional may also be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common or rare

• Bruising or bleeding at the injection site
• Mild burning along the penis
• Difficulty in ejaculating
• Swelling at the injection site

Phentolamine injected into the penis may cause tingling at the tip of the penis. This is not a cause for concern.

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

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

In the U.S.

• OraVerse
• Regitine

Available Dosage Forms:

• Powder for Solution

Therapeutic Class: Antihypertensive

Pharmacologic Class: Alpha-Adrenergic Blocker

To give the 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. It 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 are 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.

To reverse the effects of a soft-tissue anesthetic medicine, a dentist or other trained health professional will give you this medicine. This medicine is usually injected at the same spot where you have received the local dental anesthesia.

Dosing

The dose of this medicine 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 this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

• For injection dosage form: For the treatment of impotence: Adults— 0.5 to 1 milligram (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

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.