WASHINGTON – When Wayne Kanuch received a diagnosis of Parkinson’s disease in 1993, the last thing he imagined was that the drug prescribed to treat his illness would turn him into a compulsive gambler and put his libido into overdrive.
Kanuch’s marriage ended in divorce, partly as a result of the sexual pressures he placed on his wife, and he began losing fortunes at the horse track. He was fired from his job at Chevron for trolling for dates on the Internet while at work, and he quickly went bankrupt.
“I contemplated suicide a couple of times,” he said in an interview last week. “Everyone was blaming me, and I was looking at the mirror and blaming myself and asking why I could not stop.”
New evidence unearthed by scientists at the Food and Drug Administration, Duke University and other centers suggest the reason Kanuch could not stop is that the drug being used to treat Parkinson’s boosted the level of dopamine in his brain. Researchers are looking into the possibility that dopamine, which is associated with a host of obsessive behaviors, may turn some Parkinson’s patients, even those who tend to be risk-averse, into obsessive pleasure seekers.
Now, some patients are suing the manufacturers of these drugs to recover the money they lost gambling, on the grounds that the companies did not do enough to warn about these risks. Kanuch has not sued but plans to do so.
So far, there is no definitive evidence on the connection between dopamine enhancers, known as agonists, and compulsive gambling. The behavioral anomalies, though dramatic, are rare among the thousands of Parkinson’s sufferers who take the drugs. There have been no controlled studies into the possible link.
Drug manufacturers say anecdotal reports from patients such as Kanuch do not constitute scientific evidence, but they say they have updated warning labels anyway. Valeant Pharmaceuticals, which sells Permax, a dopamine enhancer, said the matter is under litigation. But it has told physicians: “As with other dopamine agonists, compulsive self-rewarding behavior (e.g., pathologic gambling) and libido increase have been reported in patients.”
Boehringer Ingelheim, which makes Mirapex, another dopamine booster, said it has toughened its warning label but said that company officials are still exploring the connection. Eli Lilly & Co, which used to sell Permax, said there is no scientific consensus on the issue and suggested that gambling problems may be linked to the increased accessibility of legalized gambling.
Still, a recent analysis headed by FDA scientist Ana Szarfman found a sharp increase in reports of pathological gambling among people taking dopamine agonists. The statistics from a federal adverse-events database are not conclusive, but FDA officials regularly mine the data to spot red flags.
“There is decent biochemical plausibility that chemical changes can lead to impulsivity and acts like pathologic gambling,” said Duke University psychiatrist P. Murali Doraiswamy, co-author of a recent report about the problem in Annals of Neurology. “It is certainly plausible that gambling can be a side effect of a drug that excessively stimulates limbic-system dopamine,” Doraiswamy said.
‘Cried my heart out’
The notion that brain chemicals play a powerful role in human behavior is at odds with American convictions about free will and choice. Kanuch and other patients said they spent years believing they were responsible for their actions, only to find that the impulse for self-destructive behaviors vanished once they stopped taking a drug.
“I broke down in tears and cried my heart out,” Kanuch said. “I could not believe a drug could cause that kind of problem. The more I read, I grew convinced and grew angrier.”
Kanuch, 52, who shuttles between living arrangements in the Texas towns of Missouri City and Katy after bankruptcy and several evictions and run-ins with the law, said he is planning to file suit against the maker of Mirapex. The man who had a 21-year career with Chevron said he lost $350,000, his marriage and numerous friends from whom he borrowed money for gambling.
Several other patients report similar obsessions. Cindy Still of Roseburg, Ore., said that after 29 years of faithful marriage, another dopamine agonist – a physician thought the drug might help ease her chronic depression – caused her to start an affair, quit her religion and become a compulsive gambler.
Peggy Andresen, 51, of Redmond, Wash., developed obsessions with gambling – and painting tables and counters to look like marble. Mirapex is a great drug, she said, but “the top of every bottle needs to have a big red sticker that says ‘May Cause Gambling.’ “
A move to turn the lawsuits into a class action was denied late last year because of the diversity of the cases, and now individual lawsuits are accumulating around the country, said Daniel Kodam, a lawyer with Soheila Azizi and Associates in Rancho Cucamonga, Calif.
Kodam dismissed the existing warnings as too little too late. “The warning label is a joke,” he said. “To bury five to six words on Page 17 when the effects are so catastrophic is ridiculous. You need a clear descriptive warning label and notification to doctors to ask patients about this potential effect.”