To Evaluate the Influence of the A118G Polymorphism in the mu Opioid Receptor Gene (OPRM1) on Effects of GSK1521498 and Naltrexone on Physiological and Behavioural Markers of Brain Function in Healthy Social Drinkers

Summary

A total of at least 48 healthy subjects with a history of social drinking will be recruited into this single-centre, randomized, double-blind, cross-over study. Subjects will be genetically stratified to result in equal numbers of A118G 'AA' homozygotes (n=24) and A118G 'G' carriers (n=24). Subjects will participate in all three treatment periods and will be randomized to receive each of the following for 5 days: Treatment A: Placebo, Treatment B: Naltrexone (NTX) 50 mg once daily (25 mg once daily for the first two days) and Treatment C: GSK1521498 10 mg once daily. A washout period will be of at least 14 days between treatments. Subjects will return for a follow-up visit 7-10 days after the final treatment session washout period has been completed. Subjects will attend the clinical research unit on days 1, 2, 3, 4 and 5 to monitor safety and tolerability for both drugs. Subjects will attend the clinical unit on days 4 and 5 for a two day assessment, using a series of pharmacodynamic measurements known to be sensitive to the effects of GSK1521498 and/or NTX: Functional brain response to alcohol and food cues; plasma cortisol; hedonic and consummatory eating behaviors; subjective response to an ethanol challenge; experimental pain threshold; and cognitive tests of attention bias towards alcohol and food cues.

Timeline

Start

2012-12-12

Primary completion

2014-05-27

Completion

2014-05-27

Drugs

Indications