Some factors affecting the plasma levels of tricyclic antidepressants.

Improved methods have been developed for accurate determination of tricyclic antidepressants and their metabolites in body fluids by means of high-performance liquid chromatography. These facilitate pharmacokinetic studies, including individual variations in drug handling, comparisons of ordinary and sustained-release preparations, assessment of side effects, and the contribution of metabolites to clinical efficacy. Comparing concentrations in erythrocytes and plasma suggests that samples of whole blood might be used for determining concentrations of some tricyclic antidepressants.