A Preliminary Study of the Effects of Venlafaxine on 24‐Hour Urinary Catecholamine Excretion Profile

Abstract

Objective: To investigate the effects of venlafaxine on the 24‐hour urinary catecholamine excretion profile in patients treated with this drug for depression.Method: Patients to be treated with venlafaxine for the management of a depressive illness were requested to provide a 24‐hour urine sample immediately before the commencement of therapy. The urinary concentrations of adrenaline and noradrenaline were determined, and the 24‐hour urinary catecholamine excretion profile was calculated. This procedure was repeated after treatment with venlafaxine for 14 days.Results: Eight patients were enrolled in the study, but three patients did not complete the protocol because of adverse drug reactions. The effects of venlafaxine treatment on the profile of urinary catecholamine excretion were assessable in five patients. The mean 24‐hour excretion of noradrenaline appeared to be decreased after venlafaxine treatment, but this decrease failed to attain statistical significance. The 24‐hour urinary excretion of adrenaline was unchanged after venlafaxine, but the ratio of noradrenaline:adrenaline urinary excretion decreased significantly after treatment.Conclusions: This small prospective study demonstrates an altered profile of urinary catecholamine excretion in patients treated with venlafaxine for depression for two weeks. Further research is needed to determine whether there is a correlation between the effects of venlafaxine on urinary noradrenaline excretion and the therapeutic and/or adverse effects of this antidepressant.Aust J Hosp Pharm 1997; 27: 232–3.