Antidepressant-induced hyponatraemia, while relatively uncommon, is an
important clinical problem with serious consequences. Most antidepres
sants have been associated with hyponatraemia. Although the exact mech
anism by which abnormalities of serum sodium level are produced is not
known, most of the patients described in case reports meet the accept
ed criteria for the syndrome of inappropriate antidiuretic hormone sec
retion. Symptoms of hyponatraemia can mimic depression of psychosis, s
o awareness of this syndrome and periodic monitoring of serum electrol
ytes are important for early recognition. Stopping the medication and
assuring normal extracellular fluid volume are the mainstay of treatme
nt; rarely, intravenous infusion of hypertonic saline is required. Aft
er correcting the metabolic abnormalities, options for treatment of de
pression include: rechallenging with the same medication or initiating
another antidepressant while carefully monitoring serum sodium level,
or considering electroconvulsive therapy, if warranted by the clinica
l condition.