[Drug induced hyponatremia. About a series of 54 cases notified to the regional center of pharmacovigilance of Saint-Étienne].

Objective: Analyze the most frequently reported drug in iatrogenic hyponatremia, explaining the mechanism in question.
Methods: Retrospective study on 54 notified cases between the Jan.1(st) 2003 and Dec. 31(st) 2009. The analysis focuses on drug classes, accountability and mechanism; risk factors, severity and the evolution of the case.
Results: Fourty-nine cases have been retained, 75,5% of the time it was an inappropriate secretion of antidiuretic hormone (SIADH) involving a selective serotonin reuptake inhibitor (SSRI) in 15 cases, an anticonvulsant in 7 cases, a proton pump inhibitor (PPI) in 7 cases or other drugs in 11. The hypo-osmolar hypovolemic hyponatremia was 12.2% of cases, incriminating a thiazide diuretic once in two. The mechanism was different or indeterminate in 12.2% of cases. In 67% cases were serious. The evolution was often favourable.
Conclusion: Drug induced hyponatremia can be serious. It must control natremia with patients at risk or symptomatic and conduct the etiological diagnosis.
(© 2011 Société Française de Pharmacologie et de Thérapeutique.)