Influence of the A118G Polymorphism of the OPRM1 Gene and Exon 3 VNTR Polymorphism of the DRD4 Gene on Cigarette Craving After Alcohol Administration … Visit link: Influence of the A118G Polymorphism of the OPRM1 Gene and Exon 3 VNTR Polymorphism of the DRD4 Gene on Cigarette Craving After Alcohol Administration