2677TT homozygotes had a drastically decreased frequency of fatigue although on morphine therapy when compared with the wild‐style ABCB1 haplotype (comprised of 10 SNPs) boosts enzyme activity by regulating mRNA expression; this could reveal A part of the phenotypic variability from the pharmacokinetics and pharmacodynamics of UGT2B7 substrates (Innocenti https://fletcheru738ncv4.targetblogs.com/profile