A multicenter randomized clinical trial of 351 CYP2D6 poor or intermediate metabolizers undergoing surgery evaluated whether pharmacogenetic-guided opioid prescribing—avoiding tramadol, hydrocodone, and codeine based on CYP2D6 genotype—improved postoperative pain control compared with usual care. Although genotype-guided prescribing increased concordance between CYP2D6 phenotype and opioid selection, it did not reduce pain intensity or opioid use at 10 days, suggesting limited clinical benefit in the context of contemporary multimodal postoperative pain management.

Source: JAMA Network Open