Parkinson’s Rx May Trigger Impulse Control Disorders

Dopamine agonists may spur pathological gambling, hypersexuality and compulsive shopping

(RxWiki News) Dopamine receptor agonists are medicines used to treat the symptoms of Parkinson’s disease. Patients who take them, however, may find themselves having trouble with impulse control.

A new study has confirmed reports that dopamine receptor agonists may be tied to pathological gambling, hypersexuality, compulsive shopping and other impulse control disorders.

The authors of the recent study called for warnings about these side effects to be included with these medications.

Thomas J. Moore, AB, of the Institute for Safe Medication Practices in Alexandria, VA, and colleagues wrote the study.

They reviewed 2.7 million adverse medication event reports from the US and abroad. They found 1,580 events that indicated an impulse control disorder.

Of these, pathological gambling was the most common, with 628 cases. There were 202 cases of compulsive shopping and 465 cases of hypersexuality — an addiction to sex or frequent increases is sexual urges or activity.

About 45 percent of the events were tied to dopamine receptor agonists.

The events occurred between 2003 and 2012. Patients were a median age of 55. About two-thirds were male.

Dopamine receptor agonists had been prescribed for Parkinson's disease in just over 6 out of every 10 cases.

Parkinson's symptoms — like shaking or trouble walking — occur when levels of the chemical messenger dopamine decrease. Nerve cells die in the brain and cause the decline. Dopamine agonists act like dopamine and stimulate those nerve cells.

Almost a quarter of those taking dopamine medications were taking them for restless leg syndrome (RLS). RLS is a neurological disorder marked by unpleasant sensations in the legs and an uncontrollable urge to move them.

The study authors looked at six dopamine receptor agonists. They were pramipexole (brand name Mirapex), ropinirole (brand name Requip), cabergoline (brand name Dostinex), bromocriptine (brand name Parlodel), rotigotine (brand name Neupro) and apomorphine (brand name Apokyn).

“Our findings confirm and extend the evidence that dopamine receptor agonist drugs are associated with serious impulse control disorders,” the authors wrote. “The effects were seen for all six dopamine receptor agonist drugs."

They stressed that none of these medications approved by the US Food and Drug Administration (FDA) have boxed warnings about their link with impulse control disorders.

"Our data, and data from prior studies, show the need for these prominent warnings,” the authors wrote.

The FDA can require manufacturers to place boxed warnings on labels or in packaging. They alert consumers that the medication might pose a health risk.

The study authors also advised doctors to monitor patients who are prescribed these medications.

In a related editorial, Joshua J. Gagne, PharmD, of Brigham and Women’s Hospital and Harvard Medical School in Boston, said doctors may have overestimated the benefit and underestimated the risk of using dopamine receptor agonists in patients with Parkinson's disease.

“In our view, these medications should be used less frequently and with great caution, paying close attention to possible untoward effects on behavior and impulse control,” he wrote.

The study and editorial were published Oct. 20 in JAMA Internal Medicine.

The authors disclosed no funding sources. Two of the study authors have been involved in civil and criminal suits about psychiatric medicines and their adverse effects. These experiences did not involve the six dopamine receptor agonists discussed in the research.

Review Date: 
October 21, 2014