Impotence Drugs in the Spotlight -- for Different Reasons

From the WebMD Archives

May 2, 2000 (Atlanta) -- One of the major concerns about Viagra is whether the impotence drug is suitable for patients with heart disease. And those taking drugs known as nitrates for heart conditions already are warned not to use the distinctive blue pills. Now another treatment for impotence has been tested on men suffering with impotence and heart disease, and the results are encouraging.

At the same time, neurologists in California are finding that Viagra gives patients with Parkinson's disease substantial relief from uncontrolled movement symptoms associated with the brain disorder.

The new drug, Uprima, was studied in nearly 1,500 patients, about 225 of whom had a history of heart disease, over the course of two months. After trying various doses of the drug, the researchers found that at the recommended dose, about one in two attempts at intercourse were likely to be successful. Those not receiving treatment had successful intercourse in less than one out of four attempts.

The research, paid for by the manufacturer TAP Holdings, was presented at a urology conference here this week.

Uprima is taken by placing it under the tongue and allowing it to be absorbed into the bloodstream. It was recommended for approval by an advisory panel to the FDA last month, even though there were concerns about Uprima's side effects. About one-third of those taking the drug at a high dose suffered from nausea or dizziness.

It's still not clear how Uprima may interact with longer-acting nitrates, although there is some indication that the combination may lead to fainting or dangerously low blood pressure. That side effect may have proven lethal to some nitrate patients who tried Viagra.

However, lead investigator for the new study, Eugene Dula, MD, says Uprima does appear safer for many heart patients. Dula is medical director of the West Coast Clinical Research in Van Nuys, Calif.

Dula tells WebMD that Viagra or Uprima should be fine for patients not taking nitrates but who take one or two drugs for high blood pressure. If they are on nitrates, especially the short-acting variety, Dula thinks Uprima may be a good option for these patients. He also says the short-acting nitrates haven't caused a profound dip in blood pressure, and that the FDA is taking a hard look at the longer-acting versions. Other doctors feel that Uprima may be a useful alternative for patients trying to cope with heart disease and impotence.

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"The nitrate studies are very small with Uprima. There's about a 10% incidence of blood pressure changes. They're not of the magnitude that occur with Viagra and nitrates, but they are somewhat concerning," John Mulhall, MD, assistant professor of urology at Loyola University Medical Center, tells WebMD.

There also are questions about Uprima's effectiveness since a relatively high percentage of those getting placebo treatments also were able to achieve an erection. "The patients that were entered into the study may not have had severe sexual dysfunction to start out with," says Patrick Walsh, MD, chief of urology at Johns Hopkins Medical Institutions in Baltimore.

Uprima is thought to work by stimulating that area of the brain responsible for causing erections. Interestingly, it's also been used to treat Parkinson's disease.

Now a new study suggests that Viagra may prove beneficial to people with Parkinson's disease. Symptoms of Parkinson's include shaking, poor balance, muscle rigidity, and dyskinesia, or abnormal, involuntary muscle movements.

In this study, presented at a neurology conference in San Diego, seven of nine Parkinson's patients treated with Viagra experienced a significant improvement in dyskinesia, with three patients reporting a complete resolution. The benefits lasted for as long as they remained on the drug and returned when the drug was discontinued. The patients continued taking their other medicines while on Viagra and experienced no worsening of their symptoms. Flushing of the face, reported by one person, was the only side effect, and there was no change in sexual function.

Neurologist David M. Swope, MD, who conducted the trial, tells WebMD he was intrigued when one of his patients, a 60-year-old man, said his Parkinson's symptoms improved after he started taking Viagra for impotence. Swope theorizes that the drug's effects may resemble those of dopamine, a chemical in the brain and nervous system known to be decreased in Parkinson's patients. Swope is assistant professor of neurology at Loma Linda University in Loma Linda, Calif.

"I was surprised it worked in these patients as well as it did," he says. "I ? wasn't expecting it to be effective in these patients." Swope warns that these findings are "very, very preliminary. We need more evidence that it actually works before it is used routinely." He is now designing another study to test the effects of Viagra more carefully. "I think [the role of Viagra] has yet to be defined, but potentially this might be a new approach to treatment."

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Vital Information:

  • A recent study suggests the drug Uprima may safely treat impotence in patients who also have heart disease.
  • A Uprima researcher says the drug seems safer than Viagra for patients who are taking nitrates for their heart conditions. Doctors still don't know the long-term effects of taking Uprima and nitrates together.
  • Researchers also are testing how Viagra might help people with Parkinson's disease control some of their movement problems.
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