Reliability of amitriptyline dose prediction based on single-dose plasma levels.
To assess prospectively the predictability of therapeutic dosage based on tricyclic antidepressant (TCA) concentrations after a single dose, 30 subjects were given amitriptyline. In the first 11 subjects maintained on a fixed amitriptyline dose regimen, predictive capacities of 18- and 24-hr single-dose levels were assessed and confirmed in relation to steady-state levels. For the other 19 subjects, the dose that would achieve a therapeutic steady-state concentration of 200 ng/ml was predicted from the 18-hr single-dose level and was rapidly instituted. Subjects achieved a mean steady-state TCA level of 204 ng/ml, with approximately 90% of the levels falling within the therapeutic range. There was clinical improvement within 2 wk in 84% of the subjects. Our results suggest that dose prediction based on TCA levels after a single dose is reliable and useful.
D000328:Adult; D000368:Aged; D000639:Amitriptyline / Q000008:administration & dosage* / Q000097:blood / Q000378:metabolism / Q000627:therapeutic use; D000929:Antidepressive Agents, Tricyclic / Q000097:blood; D003866:Depressive Disorder / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D013997:Time Factors
D000929:Antidepressive Agents, Tricyclic; D000639:Amitriptyline