A group of more than 100 individuals who were prescribed medications for the treatment of Parkinson’s disease is filing a class action lawsuit against two Australian pharmaceutical companies who market the medications. The claimants in the case allege that the medications Cabaser, an Australian brand of cabergoline marketed by the Pfizer pharmaceutical company, and Permax, an Australian brand of pergolide marketed by Aspen Pharmacare, caused a range of unrelated addiction disorders, including gambling addiction and sex addictions. Both medications are dopamine receptor agonists that mimic the presence of dopamine in the brain and are used to treat tremors caused by Parkinson’s disease.
Parkinson’s disease is a degenerative disorder that affects the central nervous system and is characterized by tremors and impaired motor skills, speech, and physical movement caused by a deficiency of dopamine in the motor cortex. There currently is no cure for the disease first identified in 1817 by English apothecary James Parkinson, but symptoms can improve with surgery or medications. Dopa-decarboxylase inhibitors are considered the ‘gold standard’ of medications in the treatment of Parkinson’s disease yet has the potential to cause problems of the liver, so dopamine receptor agonists are more commonly used for treatment. While both types of medications are prone to causing side effects, the latter has been linked with causing risk-taking behavior and impulse-control disorders such as problem gambling, sex addiction, and overeating. Pergolide, the second drug involved in the Australian lawsuit, was withdrawn from the U.S. market in 2007 following several reports of heart valves damage caused by the medication in Parkinson’s disease patients.
The Federal Court in Melbourne will hear claims from several of the individuals involved in the lawsuit on Friday, June 11. Some claimants will describe to the court how the prescription medications caused them to experience increasingly progressive gambling addictions and lost hundreds of thousands of dollars due to their problem gambling. Others relate how the medications induced compulsive sexual behavior that led to such sex addictions as pornography addiction. Their addictions, the claimants state, shattered their home lives by destroying trust, safety, and wellbeing. The individuals were prescribed the medications from 1997 to 2009, and allege that their addiction disorders ceased after quitting their medications at the end of this time frame. Both Cabaser and Permax are typically prescribed to individuals under the age of 65 who are suffering from Parkinson’s disease.
The Melbourne law firm representing the claimants will claim that the two pharmaceutical companies breached their provision of care and safety to consumers by (1) failing to properly research the possible side effects of the drugs, (2) failing to provide proper warning about the increased risks of compulsive disorders, and (3) failing to withdraw the drugs from the market after becoming aware of these increased risks.
A recent study published in the May 2010 issue of the Archives in Neurology journal researched 3,090 patients prescribed dopamine receptor agonists for the treatment of Parkinson’s disease, and found them to be 2 to 3.5 times more susceptible to impulse-control disorders. Around 13.6% of participants exhibited impulse-control symptoms, of which 5.7% engaged in compulsive shopping, 5% engaged in problem gambling, 4.3% engaged in overeating, and 3.5% engaged in compulsive sexual activity. Additionally, 3.9% had comorbid impulse-control disorders.
The study concludes that additional research to improve prevention and treatment methods is needed. Dopamine receptor agonists are currently considered effective and preferred methods of treatment for Parkinson’s disease. Health officials are aware of the drugs’ potential to cause impulse-control behaviors, but patients may not recognize symptoms right away since they develop overtime. If patients are experiencing noticeable side effects from their medications, they should immediately consult their doctor. The current claim in Australia parallels other cases against Parkinson’s disease prescriptions that have passed in the United States, Britain, and Canada.