title: Pharmacogenetics of analgesics: toward the individualization of prescription.
abstract: The use of analgesics is based on the empiric administration of a given drug with clinical monitoring for efficacy and toxicity. However, individual responses to drugs are influenced by a combination of pharmacokinetic and pharmacodynamic factors that can sometimes be regulated by genetic factors. Whereas polymorphic drug-metabolizing enzymes and drug transporters may affect the pharmacokinetics of drugs, polymorphic drug targets and disease-related pathways may influence the pharmacodynamic action of drugs. After a usual dose, variations in drug toxicity and inefficacy can be observed depending on the polymorphism, the analgesic considered and the presence or absence of active metabolites. For opioids, the most studied being morphine, mutations in the ABCB1 gene, coding for P-glycoprotein (P-gp), and in the micro-opioid receptor reduce morphine potency. Cytochrome P450 (CYP) 2D6 mutations influence the analgesic effect of codeine and tramadol, and polymorphism of CYP2C9 is potentially linked to an increase in nonsteroidal anti-inflammatory drug-induced adverse events. Furthermore, drug interactions can mimic genetic deficiency and contribute to the variability in response to analgesics. This review summarizes the available data on the pharmacokinetic and pharmacodynamic consequences of known polymorphisms of drug-metabolizing enzymes, drug transporters, drug targets and other nonopioid biological systems on central and peripheral analgesics.
authors.affiliation: Geneva University Hospital, University of Geneva, Clinical Pharmacology & Toxicology, Micheli-du-Crest Street 24, 1211 Geneva 14, Switzerland. victoria.rollason@hcuge.ch
authors.forename: Victoria
authors.initials: V
authors.lastname: Rollason
authors.forename: Caroline
authors.initials: C
authors.lastname: Samer
authors.forename: Valerie
authors.initials: V
authors.lastname: Piguet
authors.forename: Pierre
authors.initials: P
authors.lastname: Dayer
authors.forename: Jules
authors.initials: J
authors.lastname: Desmeules
mesh_terms: D000700:Analgesics / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use; D002352:Carrier Proteins / Q000235:genetics; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics; D011307:Drug Prescriptions / Q000592:standards; D014644:Genetic Variation; D006801:Humans; D008658:Inactivation, Metabolic / Q000235:genetics; D010597:Pharmacogenetics
chemical_list: D000700:Analgesics; D002352:Carrier Proteins; D003577:Cytochrome P-450 Enzyme System