Parkinson's Drugs Can Trigger Unhealthy Behaviors

12 april 2009-- A class of Parkinson's disease drugs called dopamine agonists can cause patients to develop destructive behaviors such as compulsive gambling or hypersexuality, says a new study.

Mayo Clinic researchers found that one in six patients taking therapeutic doses of dopamine agonists, such as pramipexole and ropinirole, developed unhealthy behaviors. But decreasing the dosage of these drugs may eliminate the problem.

For their study, the researchers analyzed the medical records of 267 Parkinson's disease patients treated at the Mayo Clinic in Rochester, Minn., between 2004 and 2006. Of those patients, 66 were taking dopamine agonists, including 38 who were taking therapeutic doses (doses expected to be at least minimally beneficial).

Seven of the 38 patients taking therapeutic doses of dopamine agonists developed compulsive gambling or hypersexuality after they started taking the drugs. None of the other Parkinson's patients developed those destructive behaviors, including the 28 patients taking subtherapeutic doses of dopamine agonists, or the 178 patients taking carbidopa/levodopa, the standard drug for Parkinson's.

The study is published in the April issue of Mayo Clinic Proceedings.

"It is crucial for clinicians prescribing dopamine agonists to apprise patients as well as their spouses or partners about this potential side effect. The onset can be insidious and overlooked until life-altering problems develop," Dr. J. Eric Ahlskog, a Mayo Clinic neurologist, said in a clinic news release. "It also is worth noting that the affected patients were all taking therapeutic doses. Very low doses, such as those used to treat restless legs syndrome, carry much less risk."

"For some patients, a reduction in the dose of the dopamine agonist may prove to be sufficient treatment, although total elimination of the offending drug is often necessary," Ahlskog added.