For many patients with Parkinson’s Disease, the drug Mirapex seemed to be a miracle. It offered the promise of stopping the tremors many had experienced or decades. Unfortunately, it is now apparent that Mirapex and similar drugs cause bizarre behavior in some users – with some developing gambling problems, heightened sexual interest or compulsive spending and eating habits where there had previously been no sign of compulsive behavior.
This week, the first of three “bellweather” trials concerning Mirapex and its alleged linkage to compulsive gambling is underway in U.S. District Court in Minneapolis. More than 200 people are suing Boehringer Ingelheim Pharmaceuticals, the maker of Mirapex, over compulsive behavior they say it caused. These first three trials will be used by many legal experts to gauge the strengths and weaknesses of those cases.
People with Parkinson’s lack dopamine in key areas of the brain. Mirapex and drugs like it are known as a dopamine agonist, and they work by mimicking the effects of this vital hormone and neurotransmitter. Other dopamine agonists include Requip, Parlodel, Dostinex Apokyn and Neupro.
For years, people taking Mirapex and similar drugs have complained about problems with compulsive behavior. Most of those complaints involved people who had no history of compulsive behavior before they started dopamine agonist therapy, and most reported that the behavior stopped as soon as they quit using the drugs. Several small studies, including one published in 2005 by Mayo Clinic researchers, found a link between the drugs and compulsive behavior, especially gambling addiction. The drugs’ labeling also includes warnings about possible compulsive behavior.
In June, results from the largest study ever to investigate the connection between compulsive behavior and dopamine agonists was presented at the at the International Congress of Parkinson’s Disease and Movement Disorders conference in Chicago. That study found that more than 13 percent of patients taking dopamine agonists, sold under brand names suffer from at least one of four serious behavioral addictions.
The study, which looked at more than 3,000 patients from 46 medical centers in the United States and Canada, found that Parkinson’s patients on dopamine agonists are nearly three times more likely to have at least one impulse-control disorder compared with patients receiving other treatments.
The growing evidence that Mirapex and other similar drugs are linked to compulsive behavior has changed the way some doctors approach these medications. Dr. Eric Ahlskog, a neurologist at the Mayo Clinic who has treated Parkinson’s patients for 25 years, told The Chicago Tribune that he no longer is comfortable starting patients on dopamine agonists after three patients in his practice last year developed significant gambling and sexual problems.
Other doctors told the Tribune that while they still treat patients with dopamine agonists, they are using smaller doses. Many are also now asking the patients they treat with the drugs and their families about compulsive behaviors as part of routine patient checkups.