Abstract
BACKGROUND: The use of opioids to alleviate pain is complicated by the risk of severe adverse events and the large variability in dose requirements. Pharmacogenetics (PGx) could possibly be used to tailor pain medication based on an individual's genetic background. Many potential genetic markers have been described, and the importance of genetic predisposition in opioid efficacy and toxicity has been demonstrated in knockout mouse models and human twin studies. Such predictors are especially of value for neonates and young children, in whom the assessment of efficacy or side effects is complicated by the inability of the patient to communicate this properly. The current problem is determining which of the many potential candidates to focus on for clinical implementation. CONTENT: We systematically searched publications on PGx for opioids in 5 databases, aiming to identify PGx markers with sufficient robust data and high enough occurrence for potential clinical application. The initial search yielded 4257 unique citations, eventually resulting in 852 relevant articles covering 24 genes. From these genes, we evaluated the evidence and selected the most promising 10 markers: cytochrome P450 family 2 subfamily D member 6 (CYP2D6), cytochrome P450 family 3 subfamily A member 4 (CYP3A4), cytochrome P450 family 3 subfamily A member 5 (CYP3A5), UDP glucuronosyltransferase family 2 member B7 (UGT2B7), ATP binding cassette subfamily B member 1 (ABCB1), ATP binding cassette subfamily C member 3 (ABCC3), solute carrier family 22 member 1 (SLC22A1), opioid receptor kappa 1 (OPRM1), catechol-O-methyltransferase (COMT), and potassium voltage-gated channel subfamily J member 6 (KCNJ6). Treatment guidelines based on genotype are already available only for CYP2D6. SUMMARY: The application of PGx in the management of pain with opioids has the potential to improve therapy. We provide a shortlist of 10 genes that are the most promising markers for clinical use in this context.
