Duloxetine, a Selective Noradrenaline Reuptake Inhibitor, Increased Plasma Levels of 3-Methoxy-4-hydroxyphenylglycol but Not Homovanillic Acid in Patients with Major Depressive Disorder

OBJECTIVE: We investigated the effects of duloxetine on the plasma levels of catecholamine metabolites and serum brain-derived neurotrophic factor (BDNF) in 64 patients with major depressive disorder (MDD). METHODS: Major depressive episode was diagnosed using the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders-fourth edition (DSM-IV) according to the DSM-IV text revision (DSM-IV-TR) criteria. The severity of depression was evaluated using the 17-item Hamilton Rating Scale for Depression (HAMD-17). Blood sampling and clinical evaluation were performed on days 0, 28, and 56. RESULTS: Duloxetine treatment for 8 weeks significantly increased the plasma 3-methoxy-4-hydroxyphenylglycol (MHPG) levels but not the homovanillic acid (HVA) levels in responders with MDD. CONCLUSION: These results imply that noradrenaline plays an important role in alleviating depressive symptoms.