The risk of heart-valve problems associated with two drugs used for Parkinson's disease may be far greater than previously thought, a pair of new studies suggests.
One of the drugs, pergolide, is sold by Eli Lilly as Permax and other brands and is also used to treat restless leg syndrome, according to a report in the Associated Press. The other, cabergoline, is sold by Pfizer as Dostinex, Cabaser and other names, and is mostly used in Europe.
In one study, Italian researchers found that about a quarter of Parkinson’s patients taking pergolide or cabergoline 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 last Thursday’s New England Journal of Medicine.
The valve problems are similar to the heart-related mechanism triggered by the fen-phen diet pills, noted a pharmacology professor from the University of North Carolina at Chapel Hill cited by the AP report. The professor, Dr. Bryan Roth, published a paper warning of the linkage several years ago. The combination diet pills were pulled from the market in 1997.
Lilly added valve damage to the potential side effects listed on Permax’s package insert in 2003, but the company said the risk was extremely low, five in 100,000 users.
Valeant Pharmaceuticals owns the US rights to Permax and says the drug is safe and effective. But Valeant is no longer promoting the product. All such drugs should be used “with caution,” the statement says, according to the AP report.
Cabergoline is approved in the US for treating a hormone problem, excessive prolactin in the blood, but not Parkinson’s, notes the AP.