Impotence Drugs in the Spotlight -- for Different Reasons
"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."