Consumer Group Urges FDA to Add Warnings About Impulsive Behaviors to Labels on Parkinson’s Drugs

All six dopamine agonists are implicated

Public Citizen, a consumer advocacy group based in Washington, D.C., has urged the FDA to add serious warnings to the labeling for Parkinson’s disease (PD) drugs to reflect reports of unusual adverse effects, such as sudden sexual urges, compulsive eating and shopping, and pathological gambling.

In a petition filed with the FDA, the group has called for the immediate addition of a boxed warning to the product labeling for all dopamine agonist drugs currently approved in the U.S. (apomorphine, bromocriptine, cabergoline, pramipexole, ropinirole, and rotigotine) describing the risk of developing certain impulse-control problems and compulsive behaviors.

The group also encouraged the FDA to establish a risk evaluation and mitigation strategy (REMS) for dopamine agonists that includes the requirement that a “Dear Health Care Provider” letter be distributed to doctors and health care providers, and that a medication guide be distributed to patients with all new and refill prescriptions for dopamine agonist drugs. The letter and the guide would warn doctors and patients about the risk of certain impulse-control problems and compulsive behaviors, and instruct them in appropriate measures to reduce the risk of developing such behaviors and to recognize and mitigate the harms from these adverse reactions when they occur.

In its petition, Public Citizen examined the results from more than 80 studies regarding the link between certain impulse-control problems and compulsive behaviors and the use of dopamine agonist drugs. Beginning in the 1980s, case reports were published that suggested a relationship between older dopamine agonists and certain impulse-control disorders (ICDs) and compulsive behaviors in patients with PD, according to the group’s findings. In the largest cross-sectional study published to date, the DOMINION trial (N = 3,090), Weintraub and colleagues found a prevalence of 17.1% of any ICD in PD patients taking dopamine agonists compared with 6.9% of PD patients not taking dopamine agonists.

“When estimating increased risk for developing an ICD with dopamine agonist exposure in PD patients, researchers have found odds ratios as high as 20,” the consumer group reported.

In its petition, Public Citizen also maintained that current labeling is unhelpful because the risks of dopamine agonists are described inconsistently, are often easily overlooked, or, in some cases, are misleading. Moreover, the group complained that not all manufacturers distribute product inserts, which contain cautionary messages about a medication for patients.

This isn’t the first time such warnings have been recommended, according to the STAT website. Two years ago, researchers in a paper published in JAMA Internal Medicine found that ICDs were more closely associated with dopamine agonist drugs than had been previously demonstrated and called for boxed warnings. “The associations were significant; the magnitude of the effects was large; and the effects were seen for all six” drugs, they wrote.

Sources: STAT; June 29, 2016; and Public Citizen; June 29, 2016.