title: Enantioselective analysis of citalopram and escitalopram in postmortem blood together with genotyping for CYP2D6 and CYP2C19.
abstract: Citalopram is marketed as a racemate (50:50) mixture of the S(+)-enantiomer and R(-)-enantiomer and the active S(+)-enantiomer (escitalopram) that possess inhibitory effects. Citalopram was introduced in Sweden in 1992 and is the most frequently used antidepressant to date in Sweden. In 2002, escitalopram was introduced onto the Swedish market for treatment of depression and anxiety disorders. The main objective of this study was to investigate S(+)-citalopram [i.e., the racemic drug (citalopram) or the enantiomer (escitalopram)] present in forensic autopsy cases positive for the presence of citalopram in routine screening using a non-enantioselective bioanalytical method. Fifty out of the 270 samples found positive by gas chromatography-nitrogen-phosphorus detection were further analyzed using enantioselective high-performance liquid chromatography. The 50 cases were genotyped for CYP2D6 and CYP2C19, as these isoenzymes are implicated in the metabolism of citalopram and escitalopram. In samples positive for racemic citalopram using the screening method for forensic autopsy cases, up to 20% would have been misinterpreted in the absence of an enantioselective method. An enantioselective method is thus necessary for correct interpretation of autopsy cases, after the enantiomer has been introduced onto the market. The percentage of poor metabolizers was 6% for CYP2D6 and 8% for CYP2C19.
authors.affiliation: Clinical Pharmacology, Faculty of Health Sciences, Linköping University, S-581 85 Sweden. bjorn.carlsson@lio.se
authors.forename: Björn
authors.initials: B
authors.lastname: Carlsson
authors.forename: Anita
authors.initials: A
authors.lastname: Holmgren
authors.forename: Johan
authors.initials: J
authors.lastname: Ahlner
authors.forename: Finn
authors.initials: F
authors.lastname: Bengtsson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics* / Q000502:physiology; D002423:Cause of Death; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D015283:Citalopram / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics; D065731:Cytochrome P-450 CYP2C19; D019389:Cytochrome P-450 CYP2D6 / Q000235:genetics* / Q000502:physiology; D004247:DNA / Q000235:genetics; D005260:Female; D049429:Forensic Pathology / Q000379:methods; D053593:Forensic Toxicology / Q000379:methods; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D013237:Stereoisomerism; D055815:Young Adult
chemical_list: D015283:Citalopram; D004247:DNA; D001189:Aryl Hydrocarbon Hydroxylases; C045793:CYP2C19 protein, human; D065731:Cytochrome P-450 CYP2C19; D019389:Cytochrome P-450 CYP2D6