Steady-state plasma concentrations of cis- and trans-10-OH amitriptyline metabolites.
Plasma concentrations of the geometric isomers of 10-OH amitriptyline (10-OH AT) and 10-OH nortriptyline (10-OH-NT) were determined by reversed-phase high-pressure liquid chromatography. Steady-state concentrations of At, NT, and the four 10-OH metabolites were measured in 27 patients taking AT for depression. All of the unconjugated hydroxylated metabolites were usually detectable and trans-10-OH NT always predominated. Mean concentrations, expressed as percentage of the sum of all six compounds, were: AT 30%, NT 27%, cis-10-OH AT 1.1%, trans-10-OH AT 4.0%, cis-10-OH NT 4.0%, and trans-10-OH NT 33%. Repeated measurements on 10 patients over several weeks indicated that interindividual variations in absolute and relative 10-OH metabolite concentrations are much greater than day-to-day variations. Five patients who also received a phenothiazine had a lower proportion of 10-OH metabolites.
D000328:Adult; D000368:Aged; D000639:Amitriptyline / Q000097:blood*; D014150:Antipsychotic Agents / Q000494:pharmacology; D001711:Biotransformation; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004347:Drug Interactions; D005260:Female; D006801:Humans; D006900:Hydroxylation; D008297:Male; D008875:Middle Aged; D010640:Phenothiazines; D013237:Stereoisomerism
D014150:Antipsychotic Agents; D010640:Phenothiazines; D000639:Amitriptyline