Tricyclic antidepressant plasma levels: the state of the art and clinical prospects.

The authors review the main pharmacological factors playing a role in the kinetics of tricyclic antidepressant plasma levels. The current data concerning the relationship between tricyclic plasma levels and their clinical responses indicate that there is a therapeutic window at 50-150 ng/ml for the secondary derivatives (nortriptyline and desipramine). The lower limit of efficiency for the primary derivatives (imipramine and amitriptyline) is estimated at 200 ng/ml. The boundaries and prospects of the clinical use of antidepressant plasma levels are discussed in their various methodological aspects.