“…GSK1521498 is a novel μ-opioid receptor antagonist ( Ignar et al , 2011 ; Kelly et al , 2015 ) with some inverse agonist properties that is being investigated for the treatment of disorders of compulsive consumption of food, alcohol, and drugs. GSK1521498 has been differentiated from NTX in a series of human, animal, and cellular models in terms of its opioid receptor pharmacology, its pharmacokinetics, and its greater pharmacodynamic efficacy on functional magnetic resonance imaging (fMRI) activation by fruit juice, on consumption of food and alcohol, and on behavioral models of drug seeking behavior for heroin, cocaine, and alcohol ( Ignar et al , 2011 ; Rabiner et al , 2011 ; Kelly et al , 2015 ; Giuliano et al , 2012 , 2013 , 2015 ; Ripley et al , 2015 ). In humans, GSK1521498 reduced the pleasurable response to high-fat/high-sugar food samples ( Nathan et al , 2012 ; Ziauddeen et al , 2013a ), food intake ( Ziauddeen et al , 2013a ), attentional bias to foods ( Chamberlain et al , 2012 ), and fMRI activation by food images ( Cambridge et al , 2012 ).…”