Two "dopamine agonist" drugs commonly used to treat Parkinson’s disease — pergolide (Permax; Eli Lily) and cabergoline (Dostinex; Pfizer) — may raise the risk of heart valve regurgitation, according to the findings of two European studies appearing in The
New England Journal of Medicine this week.
The new findings support what has been seen in earlier studies.
In the first study, Dr. Rene Schade, from Charite-Universitatsmedizin Berlin, and colleagues assessed dopamine agonist use among 31 patients who were prescribed a drug for Parkinson’s disease and were later diagnosed with cardiac valve regurgitation, in which the valve fails to seal properly in the reverse-flow direction. Each case patient was matched to up to 25 "control" subjects by age and sex.
The case patients included six taking Permax, six on Dostinex and 19 who had not taken any dopamine agonist in the last year.
The investigators found that current use of Permax or Dostinex raised the risk of valve regurgitation by 7.1- and 4.9-fold, respectively. Taking other dopamine agonists seemed to have no effect on the risk of cardiac valve regurgitation.
In the second study, Dr. Renzo Zanettini, from the Istituti Clinici di Perfezionamento in Milan, and colleagues assessed valve regurgitation in 64 Permax users, 49 Dostinex users, 42 users of other dopamine agonists, and 90 control subjects.
Regurgitation was noted in roughly 23 percent of Permax users, 29 percent of Dostinex users, none of the users of other dopamine agonists, and 6 percent of controls. The severity of regurgitation with Permax and Dostinex seemed to increase with the dosage of the drugs.
In a related commentary, Dr. Bryan L. Roth, from the University of North Carolina at Chapel Hill, notes that in addition to stimulating dopamine receptors, both Permax and Dostinex stimulate serotonin receptors, a key step in the progression of drug-induced valve disease.
Roth advises doctors to avoid prescribing drugs that are potent serotonin receptor agonists such as Permax and Dostinex.
