An opioid antagonist, the naltrexone, has been studied to treat ICDs in PD. Papay and al 2014 have found that patients treated by naltrexone showed an interesting decrease of their ICDs measured by the QUIP RScale. Nevertheless, naltrexone has shown adverse effects such as increasing hepatic liver enzymes. Nalmefene has no known hepatic adverse effects. Nalmefene is an opioid antagonist that has an antagonist action on μ and δ receptors, but also an agonist action on κ receptor. Grant and al 2006 has shown significant reduction of the severity of pathological gambling in patients treated with nalmefene.