In methadone-treated AA OD subjects, a GWAS identified a genome-wide significant association with methadone dose, with the nearest gene being OPRM1. This same SNP was associated with increased morphine dose in an independent sample of AA surgical patients. We also found evidence that previously identified opioid analgesic dose-associated SNPs (mapping to three different genomic locations, all separate from OPRM1) associated to higher methadone dose in the total sample of methadone-treated OD subjects. These results therefore indicate that the top genetic predictors of opioid dose in the setting of addiction treatment also influence the opioid dose needed to achieve analgesia, and vice-versa.
