The New England Journal of Medicine has published two new studies that confirm that the Parkinson’s drugs Permax (generic pergolide) and Dostinex (generic cabergoline) increase the risk of heart valve damage. Permax and Dostinex have also been prescribed to treat the tremors associated with restless leg syndrome. Permax is manufactured by Ili Lilly & Co., and Dostinex is manufactured by Pfizer, Inc. The type of heart valve damage these drugs cause is the same problem that led to the recall of the diet drug combination known as Phen-Fen.
As the heart muscle contracts and relaxes, the valves open and close, letting blood flow into the ventricles and out to the body at alternate times. Heart valves can have one of two malfunctions:
Regurgitation: The valves do not close completely, causing the blood to flow backward instead of forward through the valve.
Stenosis: The valve openings become narrowed or do not form properly, inhibiting the flow of blood out of the ventricle or atria. The heart is forced to pump blood with increased force in order to move blood through the stiff stenotic valves.
Heart valves can have both malfunctions at the same time. When heart valves fail to open and close properly, the implications for the heart can be serious, possibly hampering the heart’s ability to pump blood adequately through the body. Heart valve problems are one cause of heart failure.
In a study conducted in Great Britain, the medical records of over 11,000 patients showed that patients taking the highest doses of Permax had a 37 times greater risk of developing heart valve damage than those who took other drugs. The patients taking the highest doses of Dostinex had a 50.3 times greater risk of developing heart disease.
The Food and Drug Administration (FDA) announced Permax was withdrawn from the market in March 2007; Dostinex has not yet been recalled and carries only the precaution of heart valve damage.