title: OPRM1 and CYP2B6 gene variants as risk factors in methadone-related deaths.
abstract: Methadone is a medication valued for its effectiveness in the treatment of heroin addiction; however, many fatal poisonings associated with its use have been reported over the years. We have examined the association between CYP2B6 and micro-opioid receptor (OPRM1) gene variations and apparent susceptibility to methadone poisoning. Genomic DNA was extracted from postmortem whole blood of 40 individuals whose deaths were attributed to methadone poisoning. The presence of CYP2B6*4,*9, and *6 alleles and the OPRM1 A118G variant was determined by SNP genotyping. CYP2B6 *4, *9, and *6 alleles were found to be associated with higher postmortem methadone concentrations in blood (P < or = 0.05). OPRM1 A118G was also associated with higher postmortem methadone concentrations in blood but not to a level of statistical significance (P = 0.39). In these methadone-related deaths, OPRM1 118GA was associated with higher postmortem benzodiazepine concentrations (P = 0.04), a finding not associated with morphine-related deaths. The risk of a methadone-related fatality during treatment may be evaluated in part by screening for CYP2B6*6 and A118G.
authors.affiliation: Centre for Forensic Sciences, Bournemouth University, Dorset, UK. hbunten@bournemouth.ac.uk
authors.forename: H
authors.initials: H
authors.lastname: Bunten
authors.forename: W J
authors.initials: WJ
authors.lastname: Liang
authors.forename: D J
authors.initials: DJ
authors.lastname: Pounder
authors.forename: C
authors.initials: C
authors.lastname: Seneviratne
authors.forename: D
authors.initials: D
authors.lastname: Osselton
mesh_terms: D000293:Adolescent; D000328:Adult; D000483:Alleles; D000701:Analgesics, Opioid / Q000506:poisoning*; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics*; D065702:Cytochrome P-450 CYP2B6; D005260:Female; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods; D008691:Methadone / Q000506:poisoning*; D008875:Middle Aged; D010089:Oxidoreductases, N-Demethylating / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D017450:Receptors, Opioid, mu / Q000235:genetics*; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult
chemical_list: D000701:Analgesics, Opioid; C485764:OPRM1 protein, human; D017450:Receptors, Opioid, mu; D001189:Aryl Hydrocarbon Hydroxylases; C585599:CYP2B6 protein, human; D065702:Cytochrome P-450 CYP2B6; D010089:Oxidoreductases, N-Demethylating; D008691:Methadone