Parkinson's Drug Tied to Heart Problems
Study finds Permax can damage valves
WEDNESDAY, April 28, 2004 (HealthDayNews) -- A new study confirms previous anecdotal findings that the Parkinson's disease drug pergolide can damage heart valves, and patients may need to have surgery to correct the problem.
Lead researcher Dr. Richard B. Dewey Jr., an associate professor of neurology from the University of Texas Southwestern Medical Center, believes the drug, sold as Permax, should be taken off the market.
Pergolide has been widely used for treating the symptoms of Parkinson's disease for two decades. It is a dopamine agonist that stimulates the production of dopamine, which improves Parkinson's symptoms.
In their study, Dewey and his colleagues looked at 46 patients taking Permax for Parkinson's. They presented their findings on April 28 at the American Academy of Neurology's annual meeting in San Francisco.
Each patient had an echocardiogram, an ultrasound of the heart. Dewey's team compared these echocardiograms with echocardiograms in 46 normal older adults.
"On average, there was about a threefold increase risk of heart valve damage in the Parkinson's patients compared with the normal patients," Dewey said.
"If you look at the damage to the tricuspid valve, the risk was even higher -- at about a 14-fold greater risk," he added. The more Permax you take and the longer you take it also increases the risk for heart damage.
Based on these findings, Dewey said "there is a significant probability that Permax damages heart valves. The scary thing about it is that it is asymptomatic at first, until it's very advanced and you have major heart disease."
This damage can lead to heart failure and the need for open-heart surgery to replace the valves, Dewey said.
The researchers believe this problem is exclusive to Permax, which is similar to the diet drug "fen-phen," banned by the U.S. Food and Drug Administration for causing similar valve problems.
The newer dopamine agonists ropinirole (Requip) and pramipexole (Mirapex) are totally different and probably don't cause this problem, Dewey said. But, he cautioned, "that isn't known yet."
However, Dewey believes the effect from Permax is "so serious that the drug should be taken off the market."
Dewey recommends that patients taking Permax should see their doctor and get an echocardiogram to see if there is a problem. They should discuss with their doctor whether they should continue taking Permax or switch to another drug.
Moussa A. Youdin, a professor of medicine from the Technion R&D Foundation at the Israel Institute of Technology in Haifa, said that "pergolide has a peripheral toxicity that affects heart valves."
"It may have to be removed from the list of Parkinson's disease drugs, or the patients should be told of this risk side effect. Other dopamine agonists in the same class should also be studied to determine whether this is a generalized effect of dopamine agonists or if it is associated only with pergolide," he added.
Valeant Pharmaceuticals Inc., of Costa Mesa, Calif., makes Permax. Repeated calls to Valeant for comment were not returned.
In another study presented at the American Academy of Neurology meeting, findings show the death of brain cells, which leads to Parkinson's disease, can start long before the disease is diagnosed.
The loss of nerve cells "begins about 13 years before diagnosis," said lead researcher Dr. G. Webster Ross, from the Honolulu Department of Veterans Affairs.
Ross and his team studied the brains of 12 deceased men who had Parkinson's and compared them with the brains of 174 deceased normal men.
In each brain, the researchers counted the number of neurons in a section of the brain called the substantia nigra.
They found that the men with Parkinson's disease had about 40 percent fewer neurons compared to normal subjects. With further analysis, they were able to estimate when the loss of brain cells began.
If one can identify individuals that have cell death before the clinical symptoms, "we may have an opportunity to slow the disease before the clinical signs develop," Ross said.
"The next step is to find markers that identify living people who have this process," he added.
Dr. Michael J. Zigmond, a professor of neurology at the University of Pittsburgh, said that "most of what is in this study has been known for a long time."
"We would like to be able to identify Parkinson's as early as possible," Zigmond said. "As treatments come along that are neuroprotective, it would be nice to introduce them as early as possible."