Posted by Ame Sans Vie on August 12, 2003, at 22:33:40
Parkinson's Drug Side-Effect -- Gambling?
By Maggie Fox, Health and Science CorrespondentWASHINGTON (Reuters) - A drug given to Parkinson's patients may have an unexpected side-effect -- compulsive gambling, U.S. researchers said on Monday.
An unusually large number of patients taking Mirapex gambled themselves into debt, while patients taking other drugs did not, the team at the Muhammad Ali Parkinson Research Center in Phoenix, Arizona reported.
Dr. Mark Stacy and colleagues studied more than 1,800 Parkinson's patients for a year.
Of the 529 patients who got Mirapex, sold by Pfizer subsidiary Pharmacia and Co. under the brand name pramipexole, eight developed serious gambling addictions, Stacy and colleagues reported.
"Seven men and two women were found to have gambling behavior severe enough to cause financial hardship, and two patients reported losses greater than $60,000," they wrote in their report, published in the journal Neurology.
"No subjects on levodopa therapy alone or on any other ... regimen were found to have symptoms of obsessive or excessive gambling."
The ninth gambling patient was taking another Parkinson's drug, pergolide.
"The risk of gambling problems in a Parkinson's patient is very small," Stacy cautioned in a statement released by the American Academy of Neurology, which publishes Neurology.
"However, it may be appropriate for doctors to inform patients of this potential risk, particularly in their patients taking relatively high dosages of a dopamine agonist, and with a documented history of depression or anxiety disorder."
Mirapex and pergolide, sold by Irish drugmaker Elan under the brand name Permax, are both dopamine agonists -- they activate the ability of brain cells to use dopamine.
Parkinson's disease, which affects about 1.5 million Americans, is caused when brain cells that produce dopamine die. No one knows why, but dopamine is an important message-carrying chemical involved in movement.
Symptoms start out with shaking and can progress to paralysis. There is no cure although a number of drugs can make symptoms better for a while.
The drugs eventually cause severe side-effects, which become worse than the disease itself.
Most of the patients were in advanced stages of the disease, said Stacy, who is now at Duke University in North Carolina, although none had a previous history of gambling.
Stacy's team noted that the patients they treated lived in Phoenix, with opportunities for gambling nearby. That could be a factor, they said.
The rate of pathological gambling found in the 529 pramipexole patients was 1.5 percent, only slightly higher than the reported rate in the general population, which ranges from 0.3 to 1.3 percent.
For most patients, the gambling behavior got better after their drugs were changed.
"However, this clinical observation suggests that higher dosages of dopamine agonists may be a catalyst to bringing out this destructive behavior," Stacy said.
The researchers did not say how the drugs might cause gambling.
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