INFLUENCE OF HEPARIN ON THE ASSAY OF AMITRIPTYLINE, CLOMIPRAMINE, ANDTHEIR METABOLITES

In this study the effect of the use of lithium heparin containers on t he plasma levels of amitriptyline, clomipramine, and their metabolites was investigated. Twenty-five patients (10 men and 15 women, mean age 51.8 +/- 14.9 years) taking either amitriptyline or clomipramine in a daily dosage varying from 50 to 250 mg entered the study after giving informed consent. From each patient, blood samples were taken in a so dium edetate container and in a lithium heparin container in random or der. Parent compound levels are equal in sodium edetate and lithium he parin containers. Metabolite levels are 5.6% lower in lithium heparin containers. This difference is not considered clinically relevant.