Parkinson's Drugs Linked to Gambling
High Dopamine Agonists Doses May Lead to Gambling Addiction
Aug. 11, 2003 -- Researchers say that high doses of some medications used to treat Parkinson's disease may make some patients more likely to develop a gambling addiction.
During a recent study, published in the August 12 issue of Neurology, researchers discovered an unusual finding: Excessive gambling may be a possible side effect of dopamine agonists -- drugs often taken for the degenerative brain disorder.
Parkinson's disease causes the nerve cells that produce dopamine to die. Drugs such as Requip, Mirapex, and Permax are common dopamine agonists. They work by activating the dopamine receptor in the brain. Ultimately, they mimic or copy the function of dopamine -- a chemical that transmits signals between areas in the brain that, when working normally, coordinate smooth and balanced muscle movement.
Researchers at Muhammad Ali Parkinson's Research Center in Phoenix examined the data of nearly 2,000 Parkinson's patients over the course of one year. Of those volunteers, 529 were taking Mirapex, 421 took Requip, and 331 were treated with Permax.
Gambling Trouble With Two of Three Drugs
Nine of those patients were diagnosed as pathological gamblers -- a major psychiatric disorder characterized by uncontrolled gambling.
Most of the nine patients were in the advanced stage of Parkinson's for more than 11 years before their gambling problems began. The patients were taking both levodopa -- a drug that the brain transforms into dopamine -- and a dopamine agonist. Eight of the patients took Mirapex as their dopamine agonist, and one patient was on Permax.
Researchers found that patients had been taking Mirapex or Permax anywhere from six months to five years before gambling problems hit. Seven patients started gambling within one month of an increased dose of their dopamine agonist. None of them had a problem gambling before taking the drugs.
Some Patients Gambled Away $60,000
The gambling problems among these patients became so severe, that two patients lost more than $60,000. Luckily, for most of them, doctors were able to get the gambling under control with new treatment.
Eight patients had the dopamine agonist switched to lower comparative dosages of Requip and the remaining patient changed to a lower dosage of Mirapex and a higher dosage of levodopa. Two of the patients who switched to Requip also required psychiatric treatment.
None of the other patients in the original sample group taking Requip or levodopa only were identified as having a gambling problem.
Risk of Gambling Small but Significant
The overall chance of pathologic gambling in Parkinson's patients regardless of therapy was 0.05%. The other dopamine agonists showed:
- 1.5% for people taking Mirapex
- 0.3% for people taking Permax
"The risk of gambling problems in a Parkinson's patient is very small," says researcher Mark Stacy, MD, medical director of the Parkinson's Disease and Movement Disorders Center at Duke University Medical Center, Durham, N.C.
"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," he says in a news release.
SOURCES: Neurology, August 2003. News Release, Neurology.