The risk of heart valve damage with two drugs for Parkinson’s disease may be far greater than was known, new research suggests.
The drugs are not the main treatment for Parkinson’s, but one is also sometimes used to treat restless legs syndrome.
A study by Italian researchers found that roughly one-fourth of Parkinson’s patients taking pergolide or cabergoline, sold as Permax, Dostinex and other brands, had moderate to severe heart valve problems. Another study, by German doctors, found that users of either drug were five to seven times more likely to have leaky heart valves than those on other types of Parkinson’s medications. Both studies were reported in today’s New England Journal of Medicine.
“This is an extraordinarily high risk,” said Dr. Bryan Roth, a pharmacology professor at the University of North Carolina at Chapel Hill.
“It’s a bad side effect. As far as I know, there are no medications that can reverse it,” and valve replacement surgery is the only solution, he said.
Roth had no role in the studies but directs a drug screening program for the National Institute of Mental Health. He also published a paper several years ago warning that these drugs appeared to trigger the same heart-related mechanism that the fen-phen diet combination did. The diet pills, sold as Pondimin and Redux, were pulled from the market in 1997 after they were linked to valve problems.
One of the Parkinson’s drugs – pergolide, sold as Permax and other brands – also is used to treat restless legs syndrome. Cabergoline, sold as Dostinex, Cabaser and other names, is mostly used in Europe.
About half a million people had taken Permax during its first 14 years on the market when its developer, Eli Lilly and Co., added valve damage to the potential side effects listed on the package insert in 2003. But the company said the risk was extremely low – five in 100,000 users.
Roth believed there were more cases, a theory he said the new studies confirmed.
“This is an example of, if you don’t look for it, you don’t see it,” said Dr. C. Warren Olanow, chairman of neurology at Mount Sinai School of Medicine in New York, who had no role in the work. The findings will lead more doctors to prescribe other Parkinson’s treatments, he said.
About 1.5 million Americans and 6 million people worldwide have Parkinson’s disease, which results in tremors, loss of muscle control and sometimes death.