Caused by: Pramipexole (Mirapex) and ropinirole (Requip), used to treat Parkinson’s and restless legs syndrome (RLS), which causes a strong urge to move the legs, especially at night and when sitting or lying down.
What happens: In addition to reducing unwanted movement, those drugs, called dopamine agonists, can affect the part of the brain responsible for impulse control. About 20 percent of people taking one of them for Parkinson’s show compulsive behavior that may involve binge eating, sex, shopping, and gambling, according to a two-year study of 321 patients published by Mayo Clinic researchers. Those patients who took higher doses saw higher rates of the side effect.
What to do: Tell your doctor if you have a history of compulsive behavior, and make sure that family members know about the risk. You might not be able to tell when your behavior becomes a problem.
http://www.consumerreports.org/cro/index.htm