Guidelines for therapeutic monitoring of tricyclic antidepressant plasma levels.

A brief review of the literature surrounding the relationship between plasma levels of tricyclic antidepressants currently available in the United States and clinical efficacy is presented. While therapeutic ranges for plasma levels of some tricyclic antidepressants are reasonably well established, the relationships between plasma levels of others and clinical efficacy require further clarification. Conditions under which plasma level measurements are clinically useful and factors that alter steady-state plasma levels are discussed.