Erectile Dysfunction Treatment

Definition

Drugs and devices that treat erectile dysfunction (ED), the inability to achieve or maintain an erection long enough to engage in sexual intercourse.

Purpose

The purpose of ED treatment is to allow men to achieve and maintain an erection of sufficient strength and duration to engage in sexual intercourse.

Precautions

Because sexual activity can stress the heart, men who have heart problems should check with their physician to see if sexual activity is recommended. Erectile dysfunction drugs may trigger temporary hypotension (low blood pressure) and is known to increase cardiovascular nerve activity, so physicians should prescribe them with caution in men with a history of heart attack, atherosclerosis (hardening of the arteries), angina, arrhythmia, and chronic low blood pressure problems. ED drugs are not labeled or approved for use by women or children, or by men without erectile dysfunction. Anyone experiencing cardiovascular symptoms such as dizziness, chest or arm pain, and nausea when participating in sexual activity after taking an ED medication should stop the encounter. They should also not take any ED drug again until they have discussed the episode with their healthcare provider. It is recommended that men with kidney or liver impairments, and men over age 65, start at the lowest possible dosage of ED medications.

Description

There are three prescription medications available in the United States to treat the physical causes of ED: sildenafil citrate (Viagra), vardenafil (Levitra), and tadalafil (Cialis). They help about three-fourths of all men who try them in the general population. Several studies have indicated that their success rate in diabetic men may be slightly lower, averaging around 60-65%. All three pills work by enhancing the effects of nitric oxide. This chemical relaxes muscles in the penis to allow more blood to flow in. These pills do not cause an erection by themselves. Sexual stimulation is also required. Sildenafil or vardenafil should be taken about an hour before sex. Each is effective for roughly four hours. Tadalafil lasts for up to 36 hours. Men should not have sex more than once every 24 hours after using these drugs. Before Viagra's approval in 1998, drug treatment of erectile dysfunction was limited to alprostadil (prostaglandin), either injected into the penis or inserted as a pellet into the urethra. Sales of the three newer ED drugs reached $3.4 billion in 2004, according to the research firm IMS Health. In 2004, Viagra had about 66% of the market share for ED drugs compared to 19% for Levitra and 14% for Cialis.

Viagra

Sildenafil was originally developed in 1991 as a treatment for angina, or chest pain. The drug, marketed under the name Viagra, received FDA approval as a treatment for erectile dysfunction in March 1998, and since that time it has been prescribed for more then 20 million men worldwide. It was the first oral medication approved for ED treatment. Viagra is a vasodilator, a drug that has the effect of dilating the blood vessels. It works by improving blood circulation to the penis, and by enhancing the effects of nitric oxide, the agent that relaxes the smooth muscle of the penis and regulates blood vessels during sexual stimulation, allowing the penis to become engorged and achieve an erection.

The average recommended dose of Viagra is 50 mg. It comes in doses of 25 mg., 50 mg., and 100 mg to. The medication is taken approximately one hour before sexual activity is planned, and may remain effective for up to four hours. One drawback is that to be effective, it should be taken on an empty stomach. Also, high-fat foods can interfere with the absorption of Viagra. Viagra does not increase sexual desire. Sexual stimulation and arousal are required for it to be effective.

Levitra

In early 2003, a second prescription drug to treat erectile dysfunction, Levitra, was approved by the FDA. Like Viagra, Levitra helps increase blood flow to the penis and may help men with ED get and keep an erection. Once a man has completed sexual activity, blood flow to the penis should decrease and the erection should go away. Levitra should be taken approximately 60 minutes prior to sexual activity. In clinical trials, most patients were able to begin sexual activity before that time. A 2004 study showed that about 50% of men taking Levitra experienced a firm erection within 25 minutes and a small percentage in as quickly as 10 minutes. Studies also showed that Levitra improved erectile function in men who had other health factors, such as diabetes or prostate surgery.

Men taking nitrate drugs, often used to control chest pain (also known as angina), should not take Levitra. Men who use alpha-blockers, sometimes prescribed for high blood pressure or prostate problems, also should not take Levitra. Such combinations could cause blood pressure to drop to an unsafe level. Levitra is available in 2.5 mg, 5 mg, 10 mg, and 20 mg tablets.

Cialis

Cialis is the third oral drug prescribed to treat erectile dysfunction, approved by the FDA in November 2003. Its most notable difference from Viagra and Levitra, which work for about four hours, is that Cialis works for up to 36 hours. Cialis helps increase blood flow in the penis when a man is sexually stimulated. It can help men with ED get and keep an erection satisfactory for sexual activity. Once a man has completed sexual activity, blood flow to his penis decreases, and his erection goes away. Cialis is clinically proven to improve erectile function in most men with ED, including those with mild, moderate or severe ED.

The most common side effects with Cialis are headache, upset stomach, back pain, and muscle aches. These side effects usually go away after a few hours. Patients who get back pain and muscle aches usually get it 12 to 24 hours after taking Cialis. Back pain and muscle aches usually go away by themselves within 48 hours.

Cialis comes in 5 mg., 10 mg. (the recommended starting dose), and 20 mg. tablets. Since the absorption of Cialis is not affected by food or high-fat foods, it does not need to be taken on an empty stomach. Studies show that in most men, Cialis begins working in about 30 minutes and may be taken up to once per day by most patients.

The cost of Viagra, Levitra, and Cialis is about $10 per dose and is covered by most insurance plans.

Although the commercial availability of Viagra, Levitra, and Cialis has been useful in many men, prostate cancer patients and ED caused by psychological problems often require alternative treatment. A commonly used alternative consists of a three-drug injection containing alprostadil, papaverine hydrochloride, and phentolamine mesylate. Though it is commonly referred to as the "Knoxville formula," apparently for the city of its original introduction, a number of slightly varying formulas have been in use around the country. The three-drug preparation is administered by injection into the corpora cavernosa to induce erection.

Other traditional therapies for ED include vacuum pump therapy, injection therapy involving injecting a substance into the penis to enhance blood flow, and a penile implantation device. In rare cases, if narrowed or diseased veins are responsible for ED, surgeons may reroute the blood flow into the corpora cavernosa or remove leaking vessels.

In vacuum pump therapy, a man inserts his penis into a clear plastic cylinder and uses a pump to force air out of the cylinder. This forms a partial vacuum around the penis, which helps to draw blood into the corpora cavernosa. The man then places a special ring over the base of the penis to trap the blood inside it. The only side effect with this type of treatment is occasional bruising if the vacuum is left on too long.

Injection therapy involves injecting a substance into the penis to enhance blood flow and cause an erection. The FDA approved a drug called alprostadil (Caverject) for this purpose in 1995. Alprostadil relaxes smooth muscle tissue to enhance blood flow into the penis. It must be injected shortly before intercourse. Another, similar drug that is sometimes used is papaverine. Either drug may sometimes cause painful erections or priapism that must be treated with a shot of epinephrine. Alprostadil may also be administered into the urethral opening of the penis. In MUSE (medical urethral system for erection), the man inserts a thin tube the width of a spaghetti noodle into his urethral opening and presses down on a plunger to deliver a tiny pellet containing alprostadil into his penis. The drug takes about 10 minutes to work and the erection lasts about an hour. The main side effect is a sensation of pain and burning in the urethra, which can last about five to 15 minutes. The injection process itself is often painful

Implantable penile prostheses are usually considered a last resort for treating erectile dysfunction. They are implanted in the corpora cavernosa to make the penis rigid without the need for blood flow. The semi-rigid type of prosthesis consists of a pair of flexible silicone rods that can be bent up or down. This type of device has a low failure rate but, unfortunately, it causes the penis to always be erect, which can be difficult to conceal under clothing.

The inflatable type of device consists of cylinders that are implanted in the corpora cavernosa, a fluid reservoir implanted in the abdomen, and a pump placed in the scrotum. The man squeezes the pump to move fluid into the cylinders and cause them to become rigid. (He reverses the process by squeezing the pump again.) While these devices allow for intermittent erections, they have a slightly higher malfunction rate than the silicon rods. Men can return to sexual activity six to eight weeks after implantation surgery. Since implants affect the corpora cavernosa, they permanently take away a man's ability to have a natural erection.

Preparation

No preparation is needed for Viagra, Levitra, or Cialis.

Aftercare

The primary aftercare is to monitor blood pressure following use of ED medications.

KEY TERMS

Angina— A condition in which lack of blood to the heart causes severe chest pain.

Arrhythmia— An irregularity in the normal rhythm or force of the heartbeat.

Atherosclerosis— An arterial disease in which raised areas of degeneration and cholesterol deposits (plaques) form on the inner surfaces of the arteries. Also called hardening of the arteries.

Corpora cavernosa— Either of a pair of columns of erectile tissue at either side of the penis that, together with the corpus spongiosum, produce an erection when filled with blood.

Priapism— A prolonged erection lasting more than four hours.

Vasodilator— An agent, such as a nerve or hormone, that widens the blood vessels, which in turn decreases resistance to blood flow and lowers blood pressure.

Risks

Priapism, a prolonged erection, is a very rare potential side effect of all prescription ED medications. Persons taking any erectile dysfunction medication who have a prolonged erection, lasting more than four hours, should seek immediate medical attention. Priapism can cause damage to the penis potentially leading to the permanent inability to have an erection.

Normal results

The goal of all ED treatments is to achieve and maintain an erection strong enough to engage in sexual intercourse, which is usually 30-60 minutes.

Abnormal results

The most common abnormal response is the failure to achieve and maintain and erection strong enough and long enough to engage in sexual intercourse.

Resources

BOOKS

Icon Health Publications. The Official Patient's Sourcebook on Erectile Dysfunction: A Revised and Updated Directory for the Internet Age. San Diego: Icon Health Publications, 2005.

Kloner, Robert A.Heart Disease and Erectile Dysfunction. Totowa, NJ: Humana Press, 2004.

Lue, Tom F. An Atlas of Erectile Dysfunction, Second Edition. London: Taylor & Francis Group, 2003.

Metz, Michael E. and Barry W. McCarthy. Coping With Erectile Dysfunction: How to Regain Confidence and Enjoy Great Sex. Oakland, CA: New Harbinger Publications, 2004.

PERIODICALS

Roberts, Shauna S. "Options Increase for Men With Erectile Dysfunction: Doctors Now Have an Array of Treatments for Men's Sexual Problems." Diabetes Forecast (September 2004): 55-58.

Sadovsky, Richard. "Sildenafil is Safe and Effective in Men With Stable CAD." American Family Physician (September 1, 2004): 955.

Tomlinson, John. "The Patient With Erectile Dysfunction." The Practitioner (February 9, 2005): 104.

Trissel, Lawrence A. "Long-Term Stability of Trimix: A Three-Drug Injection Used to Treat Erectile Dysfunction." International Journal of Pharmaceutical Compounding (May-June 2004): 231-235.

Wooten, James M. "Erectile Dysfunction: There are Now Three Effective Oral Drugs for Treating ED, Paving the Way for Nurses to Put Patients With This Condition on the Road to Good Sexual Health." RN (October 2004): 40.

Zoler, Mitchel L. "Drug Update: Erectile Dysfunction." OB/GYN News (April 15, 2004): 92.

ORGANIZATIONS

Erectile Dysfunction Information Center. 10949 Bren Road East, Minnetonka, MN 55343-9613. (866) 294-7508. [email protected]. http://www.cure-ed.org. 952-852-5560

OTHER

National Kidney and Urologic Diseases Information Clearinghouse Erectile Dysfunction. December 2003. http://kidney.niddk.nih.gov/kudiseases/pubs/impotence/ (cited March 31, 2005).