Winter Newsletter 2007

2 Parkinson’s Drugs Cited In Heart-Valve Defects

Two drugs once commonly used to treat Parkinson’s disease—pergolide and cabergoline—produce heart-valve defects in as many as a quarter of the patients using them, French and German researchers are reporting in a study published today.

Scattered findings from smaller studies already have suggested the drugs pose a risk, but the two new papers in the New England Journal of Medicine show the risk is much higher than earlier suspected.

"This is not a rare side effect," said Dr. Bryan L. Roth of the Parkinson’s Disease Foundation.

Cabergoline is approved for other uses, such as treating brain tumors, and is sometimes used off-label for treating Parkinson’s. The drugs, which are available in generic form from a variety of producers, "have been around a long time and a large number of people have potentially been exposed to them," added. Dr. Michael S. Okun, medical director of the National Parkinson Foundation. "And, the drugs are much more widely used in Europe and developing countries because they cost less than newer drugs that do the same, thing," he said.

Some patients who have done well on pergolide will decide to continue to take it, Okun said. "They will need to be monitored very closely." Similar heart-valve problems led to the withdrawal of the diet drugs fenfluramine and dexfenfluramine—part of the now notorious fen-phen drug combo—from the market in 1997.

The drugs cause the heart valves to develop fibrous deposits that produce leakage of blood back into the heart. That causes the heart to overwork, which ultimately can lead to heart failure and death. The problem is readily detected by echocardiography with ultrasound and can only be fixed by surgically replacing the damaged valve.

Parkinson’s, which strikes as many as 100,000 Americans each year, is characterized by severe tremors and rigidity in the limbs, and loss of muscle control. It results from the death of brain cells that produce the neurotransmitter dopamine, which plays a key role in transmitting commands from the brain’s muscle-control centers.

Los Angeles Times