Dopamine Drugs Pose Compulsion Risks
The Los Angeles Times on Tuesday examined the risk of compulsion from Parkinson's disease treatments that boost dopamine levels in the brain.
A University of Toronto study released in April found that as many as one in 15 people taking the drugs might develop compulsive behavior. About 50% of Parkinson's disease patients in the U.S. take dopamine drugs like Boehringer Ingelheim's Mirapex and GlaxoSmithKline's Requip.
According to the Times, "[N]o one knows how many patients develop compulsions," in part because "behaviors vary and no large clinical trial has studied the phenomenon."
Mayo Clinic researchers in the September 2005 issue of Neurology said dopamine drugs are strongly attracted to nerve cells that are in the limbic region of the brain, which controls feelings of well-being and reward.
Northwestern University scientist James Surmeier called that finding "a smoking gun."
An FDA study published in the February issue of Neurology found a "strong association" between the drugs and cases of compulsive gambling, but the total number of incidents was small, the Times reports.
Drug companies in the past year have added information about compulsive reactions to drug inserts. The companies "say they are monitoring reports, but so far the rate of compulsions does not exceed that of the general population," the Times reports.
Meanwhile, doctors are reluctant to stop prescribing the drugs because they are effective and most patients' personalities are not affected (Gellene, Los Angeles Times, 5/23).