Impotency—inability to achieve or sustain an erection—occurs most often in older men, but it isn't an inevitable consequence of aging. While psychological factors can cause impotence, at least 80 percent of all cases of sexual dysfunction are due to an underlying physiological problem that can be treated.
As men age, production of the male hormone testosterone declines, and the force and amount of semen ejaculated decreases, notes Gerald Brock, M.D., associate professor of Urology at McGill University in Montreal, Canada. "The good news is we seldom want to have children as we age, and the orgasms are still great! So in most cases it's only an academic finding without any significant consequences."
Studies have shown that testosterone is not essential for erection, but it definitely plays a role in sex drive, and erections are more frequent and rigid when a man has an adequate level of the hormone. Not only does testosterone affect libido, research has shown that it increases production of nitrous oxide in the erectile tissue of the penis (corpora cavernosa), which is important in regulating erectile function. That may be why it takes some older men longer to achieve an erection, or their erection may not be as firm or large as in the past.
Men who are impotent due to a low level of testosterone can be treated with hormone replacement therapy. However, impotence in older men is frequently the result of a medical condition or medication that interferes with erectile function. An erection requires a sequence of events, which involve nerve impulses in the brain, spinal column and penis, as well as response in muscles, fibrous tissues, veins, and arteries in and near the corpora cavernosa. Any disruption of this sequence of events can trigger impotence.
Therefore, the most common cause of impotence (70 percent) is disease that causes damage to arteries, smooth muscle and fibrous tissues, including diabetes, kidney disease, chronic alcoholism, multiple sclerosis, atherosclerosis, and vascular disease. Prostate, colon or bladder surgery--any surgery in the pelvic area--can cause impotence if nerves and arteries near the penis are injured. Smoking may also affect sexual performance, because it affects blood flow in veins and arteries. Medications that can affect erectile function includes high blood pressure drugs like lisinopril and atenolol, antihistamines, tranquilizers, appetite suppressants, and cimetidine (ulcer treatment). Additionally, antidepressant medications, especially serotonin uptake inhibitors (Luvox, Prozac, Paxil, Zoloft) may inhibit erection and delay or prevent ejaculation.
While one in three men over age 60 suffer from some form of sexual difficulty, only about 10 percent actually seek treatment. Possibly, many men suffer in silence because they're unaware of causes and treatments for impotency. In a survey, conducted by the Impotence World Association, less than five percent of respondents knew that erectile dysfunction is usually physiological, and less than 15 percent were aware of new impotency medications, such as Viagra.
Viagra® (sildenafil) and Uprima (apomorphine) are oral medications that improve a man's erection ability. However, men who become impotent following surgery may not respond to these drugs. "Viagra will only help those men who have preservation of some of the nerve fibers after the surgery. The good news is that if Viagra doesn't work, injection therapy with Caverject or other vasoactivator meds probably will help." Caverject and MUSE (Medicated Urethral System for Erection), another vasoactivator, involve self-administered injection of medication into the penis opening. However, men who don't respond to oral medications or injections may be helped with a penal implant or vacuum pump, which Dr. Brock notes is common in men with diabetes or very poor circulation. The pump, which is available without a prescription, forms a vacuum around the penis. As air is sucked out of the tube, blood flows into the penis, creating an erection.
Some studies indicate that Viagra presents a risk for men with cardiovascular diseases. However, Dr. Brock notes that the risk of heart attack depends on an individual's own risk factors, such as cholesterol level, age, and smoking among others. "People with diabetes, heart disease, and hypertension (high blood pressure) do develop heart attacks in the real world. When you have 1.5 million men, many of them with these problems, taking any medication, some will die from cardiac causes." Dr. Brock suggests that the risk for heart attack may not be higher with Viagra, but higher for the group of men likely to need Viagra. He stresses, however, that men who take nitroglycerine should not use Viagra, because it stops the body's ability to break down the chemicals in nitroglycerine.
While there is no known prevention for erection dysfunction, Dr. Brock suggests that exercise and eating a low-fat diet--the same strategies used to reduce the risk for heart disease--may be helpful, since erection is dependent on a healthy vascular system.