Report Ties Parkinson's Drugs to Gambling
Mayo Clinic Doctors Report 11 Cases in Medical Journal
"Our overall sense about this study is that we don't think there's a causal connection between [Requip] and compulsive gambling that was established by this study," Holly Russell, GlaxoSmithKline's product communications director, tells WebMD.
"It's a small, uncontrolled study of 11 patients, some of whom were on concomitant medications, including levodopa," she says.
"Only two patients were on [Requip] -- one with and one without levodopa," says Russell.
"We have looked carefully at our controlled clinical data, and we've looked at the FDA database of reports of adverse events, and at this time, there isn't sufficient evidence to indicate an association [between] compulsive gambling and the use of [Requip]."
Pattern Didn't Include Levodopa
Three of the patients were not treated with another drug, levodopa. It is the most commonly prescribed drug for controlling Parkinson's disease. Levodopa is transported to the nerve cells in the brain that produce dopamine. It is then converted into dopamine for the nerve cells to use as a neurotransmitter.
"None developed new gambling or an increase in gambling while [only taking] levodopa," write the researchers.
Four of the patients had never gambled before taking the drugs, write the doctors.
One of those patients was a 41-year-old married computer programmer. The doctors say he reported never having gambled before.
"Within one month of reaching a dose of 4.5 milligrams per day [of Mirapex], he described being 'consumed' with the need to gamble on the Internet, losing $5,000 within a few months," write the doctors.
"In addition to gambling, he compulsively purchased items that he did not need or want, plus he was fixated on having sex with his wife several times daily."
The man consulted his neurologist, who advised tapering off of Mirapex. Instead, the man chose to quit it abruptly.
"Two days later, he recognized a rapid resolution of the desire to gamble, which he described 'like a light switch being turned off'," write the doctors.
"In summary, dopamine agonist drugs appear to be uniquely implicated as a cause of pathological gambling," write the doctors.
Disproportionate stimulation of dopamine receptors in the brain may be responsible for pathological gambling in these Parkinson's disease cases, they write.