Injected medications for erection problems

Examples

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Brand Name	Chemical Name
Caverject	alprostadil

Brand Name	Chemical Name
Pavabid	papaverine hydrochloride

Brand Name	Chemical Name
Regitine	phentolamine mesylate

Some doctors have these three medications mixed together by a pharmacist. This preparation is often called Trimix.

You inject this medication into the side of the penis with a tiny needle. The shots usually are not very painful, but you may find the thought of injecting yourself uncomfortable. Less commonly, these medications also may be available in an auto-injector in which the needle is hidden, making them easier to use. You can adjust the dose of medication to create an erection that lasts the desired length of time.

See an illustration of an injection .

Your doctor may give you a trial use of this medication while you are in the office. This allows the doctor to see how well the medication works for you, see whether you can use it properly, and check for adverse reactions, such as a painfully long-lasting erection (priapism) or an allergic reaction.

How It Works

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The medications are injected into the penis before sex to relax the muscles that surround the blood vessels in the penis, increasing the blood flow into the penis and producing an erection that lasts 30 minutes to an hour or longer. How long the erection lasts depends on how much medication you inject.

Why It Is Used

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These medications may be prescribed for erection problems (erectile dysfunction) caused by psychological or physical factors.

How Well It Works

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A success rate of 85% has been reported from injections.¹

Side Effects

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Injections occasionally can result in a painful, prolonged erection (priapism). Call your doctor if an erection lasts longer than 4 hours. If the erection isn't relieved, it may damage tissues inside the penis.

Other side effects of injections may include:

• Bruising.
• Pain in the penis (usually mild to moderate). Pain in the penis was reported by about 50% of users in one study.² Injecting the medication slowly may help prevent pain. Only a few men stop using the medication because of pain.
• Formation of scar tissue in the penis (fibrosis).

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

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When investigating injections for erection problems, it is important to include your partner in your decision.

These medications are less likely to be effective for men in whom blood flow into or out of the penis is severely impaired.

They may cause problems for men with severe mental illness or for those who would have difficulty giving the injection. If you have vision problems, your partner can learn to give you the injections. Make sure your partner is comfortable with helping you and with using injections.

These medications can be used by men who are taking medication to prevent blood clots (anticoagulants, such as warfarin [for example, Coumadin]).

Medications that are injected into the penis can be given no more than every other day. Excessive use may cause scarring.

Some men may find the idea of self-injections unpleasant, or they may find self-injections difficult to do. The use of an auto-injector, in which the needle is hidden, may make the shots easier for some men to use.

Couples trying to have children may prefer injections over a vacuum device, because the vacuum device blocks ejaculation.

Up to 60% of men stop using the medications.³ Reasons include:^{3, 4}

• Partner relationship issues (being able to have erections doesn't solve relationship problems).
• The mechanical nature of the process, which interferes with spontaneity.
• Fear and discomfort about giving an injection into the penis.
• Concern about effects of long-term use.
• Development of tolerance to the medication (which rarely happens).
• Development of scar tissue.

Complete the new medication information form (PDF) (What is a PDF document?) to help you understand this medication.

References

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Citations

1. American Urological Association (2003). Non-surgical management of erectile dysfunction (ED). Available online: http://www.urologyhealth.org/adult/index.cfm?cat=11&topic=174.

2. Webber R (2003). Erectile dysfunction. Clinical Evidence (10): 1003–1011.

3. Lue TF (2004). Male sexual dysfunction. In EA Tanagho, JW McAninch, eds., Smith's General Urology, 16th ed., pp. 592–611. New York: McGraw-Hill.

4. American Urological Association (2005). Management of Erectile Dysfunction: An Update. Baltimore: American Urological Association. Also available online: http://www.auanet.org/timssnet/products/guidelines/main_reports/edmgmt/content.pdf.

Credits

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Author	Ralph Poore
Editor	Kathleen M. Ariss, MS
Associate Editor	Pat Truman
Associate Editor	Terrina Vail
Primary Medical Reviewer	Adam Husney, MD - Family Medicine
Primary Medical Reviewer	E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer	Christopher G. Wood, MD, FACS - Urology/Oncology
Last Updated	June 13, 2006