Rare but relevant: MDMA and hyponatraemia.

Conventionally used for its stimulant, empathogenic and entactogenic effects, 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) is one of the most commonly used psychoactive drugs, specifically among young adults and in nightlife and recreational party contexts. Often perceived as a safe drug, MDMA can display an array of toxic effects on multiple organs, with hyponatraemia (a low blood sodium concentration that can cause an altered mental state) being increasingly reported. Although hyponatraemia per se is among the most common electrolyte disorders encountered in clinical care, acute MDMA-induced hyponatraemia was first described in 1993 and constitutes a life-threatening condition if left untreated, particularly among women, who present higher incidence rates and increased odds of developing severe clinical effects. The present review outlines the main clinical manifestations and prevalence of MDMA-induced hyponatraemia, its pathophysiological mechanisms and the therapeutical approaches to correct this electrolyte imbalance.