Venlafaxine hyponatraemia: incidence, mechanism and management

Authors: Milton Roxanas a; Emily Hibbert b; Michael Field c
Affiliations:
a Concord Hospital, Concord, NSW, Australia
b Department of Medicine (Endocrinology), Concord Hospital, Sydney, New South Wales, Australia
c Northern Clinical School, University of Sydney, Sydney, New South Wales, Australia


Abstract
Objective: This prospective study was performed on patients aged >65 years commencing therapy with venlafaxine, in order to determine the incidence of hyponatraemia induced by the drug, to investigate the underlying pathophysiological mechanisms, and to evaluate a simple approach to management of this condition. Method: All patients aged >65 years seen by one author (MR) from all referral sources were entered into the study. Baseline biochemical tests were ordered, and if hyponatraemia developed (plasma Na <130>65 years of age should have their electrolytes measured 3-5 days after starting venlafaxine therapy. If hyponatraemia develops, it can be managed with modest fluid restriction without discontinuing drug treatment, subject to close continued clinical observation and biochemical monitoring.