Erectile dysfunction drugs aren't always effective

From: www.stltoday.com

By Dr. John Morley
08/20/2009

Since Bob Dole, the senator and presidential candidate, became the spokesman for Viagra as the cure-all for erectile dysfunction, millions of men have used the medicine or similar drugs to enhance their sexual performance. Unfortunately, it hasn't worked for all of them.

The most common reason an erectile dysfunction drug fails is because the man taking it has low testosterone levels. Many years ago, we showed that men with very low testosterone levels may be unable to obtain any kind of an erection. Testosterone is essential for the production of nitric oxide in the penis, which causes blood vessels to open. The rush of blood into the penis results in an erection.

Erectile dysfunction medicines work by allowing the chemical reactions produced by nitric oxide to last longer. Without enough nitric oxide to light the spark, though, there's no flame to fan.

Some men get erections but rapidly lose them due to a venous leak that is similar to when a car tire is punctured. Rubber bands or rings can be used to stop this slow leak.

In some cases changing between erectile dysfunction medicines solves the problem. Other times, the artery is partly blocked; taking one of the drugs every day for a week or two may clear the blockage and allow adequate erections to occur.

Cigarettes can cause impotence by keeping arteries in the penis from dilating, so kicking the habit carries extra benefits. A Brazilian urologist has shown that smoking just two cigarettes inhibits erections produced by a powerful vasodilator injected into the penis. A famous cartoonist suggested that dinosaurs became extinct when they started to smoke.

Sometimes alterations in blood pressure or other medications will solve the problem, as may proper control of blood sugar in those who have diabetes. When all else fails, direct injections into the penis, vacuum tumescence pumps or penile prosthesis may be an appropriate therapy.

Finally, be aware that most erectile dysfunction is due to atherosclerosis — plaque deposits that coat the arteries and cause cardiac disease — so have your heart checked.

SLUCare physician John Morley is director of geriatrics at St. Louis University and a geriatrician at St. Louis VA Medical Center. Email him at morley@slu.edu. The Aging Successfully column for seniors rotates each week with XX Files, a women's health column.