In August, a man who blamed the Parkinson’s Disease drug Mirapex for his gambling addiction was awarded $8.2 million in his lawsuit against the drug’s maker, Boehringer Ingelheim Pharmaceuticals Inc. It was considered a bellwether case, and was being watched by many to gauge the strengths and weaknesses of the other Mirapex lawsuits. Now, many legal experts believe that there is a good chance similar Mirapex lawsuits will be successful.

Mirapex belongs to a class of drugs known as dopamine agonists, which have long been suspected of causing compulsive behavior. Mirapex was approved by the Food & Drug Administration (FDA) in 1997 to treat Parkinson’s, and in 2006, it was approved as a treatment for Restless Leg Syndrome. Other dopamine agonists include Parlodel, Dostinex, Requip, Apokyn and Neupro.

Parkinson’s Disease occurs because of a lack of the neurotransmitter dopamine in certain areas of the brain. Dopamine works in the brain’s movement and coordination centers, and it is also involved in the brain’s pleasure response by reinforcing behaviors that provide enjoyment — including drinking, drugs, sex and gambling.

For many Parkinson’s Disease patients, Mirapex provides much needed relief from tremors. But some doctors say Mirapex and other dopamine agonists may also encourage impulsive behaviors. In some patients, Mirapex over-activates the pleasure centers in the brain. The biochemical reaction that Mirapex induces might cause some people to experience a “rush” when they are anticipating a reward or excitement.

Several studies have found a link between Mirapex and similar drugs and compulsive behaviors. According to a one presented in June at the International Congress of Parkinson’s Disease and Movement Disorders conference in Chicago, more than 13 percent of 3,090 Parkinson’s patients had a problem with compulsive gambling, buying, sex or binge-eating. People who were taking either Mirapex or Requip had a two- to three-times greater chance of having one of the four impulse-control disorders.

While other studies have found a similar association between, perhaps the most dramatic evidence of linking Mirapex to these behaviors is the fact that in most cases, the behavior stops once the drug is discontinued. Unfortunately, many people who were experiencing these side effects had no idea that Mirapex might be behind their odd behavior. Despite having evidence that Mirapex caused impulse-control behaviors from clinical trials in the 1990s, the maker of the drug did not issue warnings about the problem until 2005.

The impulse control problems experienced by Mirapex users have resulted in bankruptcies, broken marriages, depression and even suicide. As a result, more than 200 lawsuits have been filed against Boehringer Ingelheim for by Mirapex patients for its failure to warn users about the drug’s association with impulse-control disorders.

Gary Charbonneau was one of those patients. Charbonneau, who began taking Mirapex in December 1997, said he suffered from a gambling addiction from March 2002 to February 2006. In that period of time, he gambled away $260,000. The case was heard in the US District Court in Minneapolis, where hundreds of Mirapex lawsuits have been consolidated.

Charbonneau’s lawsuit not only claimed that Mirapex caused his gambling problem, but that the drug’s makers, Pfizer and Boehringer Ingelheim, knew about its potential to cause compulsive behavior, but did not issue any warnings, or take steps to investigate the true scope of the problem.

Boehringer Ingelheim, and Pfizer Inc., which marketed the drug in U.S. had argued that hey were not liable for Charbonneau’s addiction because the FDA had not asked for any label changes, despite reports that Mirapex was causing compulsive behavior. The companies also claimed that Charbonneau’s gambling problems had preceded his use of Mirapex, and continued after he stopped taking the drug.

The jury that heard the case was not convinced by the defendants’ arguments. Charbonneau was awarded all of his gambling losses, along with $7.8 million in punitive damages. However, Boehringer Ingelheim and Pfizer are expected to appeal the decision.

Charbonneau’s case was one of three “bellwether” cases that are scheduled to be heard back-to-back in the Multidistrict Litigation. The trials will be used by the other potential Mirapex plaintiffs, as well as the defendants, to assess their chances for success in other lawsuits.

By Laurie Villanueva
Pittsburgh, PA-based freelance writer.