Dopamine agonist drugs, which are used to control movement problems caused by Parkinson’s disease, may lead to pathological gambling and other compulsive behaviors, yet another study has shown. Discontinuing or reducing the dose of the drug appears to curb the compulsions.

Parkinson’s disease is a progressive neurological disorder that causes tremor, muscle rigidity and movement problems. It occurs when a region of the brain that helps control movement-and produces the brain chemical dopamine-deteriorates. Drugs used to treat Parkinson’s work by boosting dopamine levels in the brain. Dopamine is known to play a key role in the behavioral reward system, reinforcing a myriad of behaviors, such as gambling.

There have been previous reports of pathological gambling in patients taking dopamine agonists.

In the current report, to be published in the September Archives of Neurology, Dr. M. Leann Dodd and colleagues describe 11 Parkinson’s patients who started gambling between 2002 and 2004 while under treatment at the Mayo Clinic in Rochester, Minnesota.

All 11 were taking a dopamine agonist - pramipexole (sold as Mirapex) in nine cases and ropinirole (sold as Requip) in two cases. None was on levodopa monotherapy at the time of the problem behaviors.

Four of the patients had never gambled before in their lives. In seven cases the gambling started within 1 to 3 months of achieving a “maintenance” dose of the anti-Parkinson’s drug. In some cases, tens or hundreds of thousands of dollars were lost.

Other behavioral problems developed in six patients, including compulsive eating, increased alcohol use, and hypersexuality.

Within months of discontinuing or tapering the dose of the dopamine agonist, the compulsive behaviors had stopped.

In a review of the literature, Dodd’s group identified nine other reports of compulsive gambling in Parkinson patients, all of whom were taking dopamine agonists (pramipexole, pergolide, ropinirole, bromocriptine and cabergoline). Pramipexole was the agent in 68 percent of cases.

SOURCE: Archives of Neurology 2005.