Compulsive Behaviors Linked to Mirapex (pramipexole)

A group of men primarily taking pramipexole (Mirapex), a dopamine-agonist drug used to treat Parkinsons’s disease, has shown sudden onset of compulsive tendencies, including frequent gambling, hypersexuality and overeating, according to a report by Mayo Clinic Staff on 15 July.

In a study led by M. Leann Dodd, MD, a psychiatrist at Mayo Clinic in Rochester, Minnesota, all 11 study subjects taking dopamine agonists for Parkinson’s developed compulsive gambling behaviors. Similarly, in a previous study of 529 subjects taking pramipexole for Parkinson’s symptoms, 1.5% had developed compulsive gambling behaviors.

The connection between the drug and the compulsive behaviors initially came up as incidental commentary during doctor appointments, according to Dr. Dodd. “Patients or their family members would bring it up. It was mostly gambling, but over half of our patients also manifested other compulsive behaviors, such as hypersexuality or compulsive overeating.

“It started out as a curiosity, but then we found case reports that showed there might be some connection between this compulsive behavior and a particular type of medication. When people were tapered off these medications, the compulsive behavior would go away.”

Effects of Dopamine

Patients with Parkinson’s disease are deficient in dopamine, a brain neurotransmitter. Dopamine agonists, such as pramipexole (Mirapex), are essentially synthetic dopamine that binds to the brain’s dopamine receptors.

Several subtypes of dopamine receptor exist. Pramipexole binds to the “D3” dopamine receptor subtype much more often than to other types of dopamine receptors. D3 receptors are densely concentrated in an area of the brain associated with mood, behavior and rewards.

Dr. Dodd believes that the recognition of pramipexole’s radical effect on behavior may pave the way for future studies on how to curb addictive behavior in general.

Uses of Pramipexole

Pramipexole is used to treat people with Parkinson’s disease, and, at much lower doses, to treat people with restless legs syndrome. A common daily dosage of pramipexole for restless legs syndrome is 0.125 milligrams, compared with a common daily dosage of 4.5 milligrams for Parkinson’s, according to Dr. Dodd.

Interestingly, no link has yet been noted between compulsive gambling and pramipexole at the lower dosages.

Incidence of Side Effects

A study of 529 people with Parkinson’s taking pramipexole revealed that 1.5% developed compulsive gambling behaviors. Dr. Dodd’s study included only 11 people with Parkinson’s, but all started gambling compulsively during treatment with dopamine agonists.

Dr. Dodd and colleagues also measured the time between starting the drug and the onset of behaviors – most people developed gambling behaviors within 1-2 months.

Dr. Dodd also notes that, because compulsive gambling, hypersexuality and overeating are fairly embarrassing behaviors, patients may be reluctant to report them, even to their doctors. Therefore, the reported incidence may be somewhat inaccurate. Dr. Dodd encourages patients who are experiencing these behavior changes to confide in their doctors, as the effects of the drug are potentially reversible.

Sources:
Parkinson’s drug can cause compulsive gambling, by Mayo Clinic staff
Pathological gambling associated with dopamine agonist therapy in Parkinson’s disease, E. Driver-Dunckley et al., Neurology, volume 61, pages 422-423, August 2003.

Posted: July 2005


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