Tricyclic plasma levels in depressed outpatients treated with amitriptyline.

Seventy-four patients were treated with 150 mg/day amitriptyline (AT) to determine possible correlations between clinical improvement, demographic variables, and AT and nortriptyline (NT) plasma levels. Plasma level determinations after 2 and 6 weeks of treatment revealed that moderately significant correlations existed between AT plasma levels and clinical improvement, dosage intake, age, weight, sex, and coffee intake. Some of these findings were more pronounced after 2, and some after 6 weeks of treatment.