FIGURE 2.

CYP2D6 phenotype assignment and phenotype‐based opioid prescribing recommendations for participants in the intervention arm. *Based on CYP2D6 genotype and use of moderate or strong CYP2D6 inhibitors. Abiraterone, cinacalcet, duloxetine, and mirabegron are moderate inhibitors and reduce the activity score by 50%. Bupropion, fluoxetine, paroxetine, quinidine, and terbinafine are strong inhibitors that reduce the activity score to 0. ^†Phenotype definitions differs from Clinical Pharmacogenomic Implementation Consortium and Dutch Pharmacogenetics Working Group consensus definitions. Whereas sites detect copy number variation, they do not detect which allele is duplicated or multiplicated. This can result in a ranged phenotype. Given the potential for the IM and/or UM phenotype, recommendations consistent with these phenotypes are provided. In the case of copy number variation leading to ranged phenotypes, recommendations are provided to avoid hydrocodone, tramadol, or codeine for the IM to NM ranged phenotype and to avoid hydrocodone, tramadol, codeine, or oxycodone for the IM to UM and NM to UM ranged phenotypes. AS, activity score; IM, intermediate metabolizer; NM, normal metabolizer; PM, poor metabolizer; UM, ultra‐rapid metabolizer.