Pharmacogenetics of Opioid Response

For opioids requiring CYP2D6 O‐demethylation to active metabolites, poor metabolizers have reduced metabolite formation and minimal pain reduction. Clinically, this has only reliably been shown for tramadol. Ultra‐rapid metabolizers have an increased risk of toxicity especially for codeine. ABCB1 genetics show no consistent findings. In Asian populations, the high OPRM1 118A>G frequency associates with higher opioid dosage requirements. Clinical translation of opioid genetics is premature because many important pain and addiction phenotype factors contribute.