Hyponatremia Etiology and Tolvaptan: Are we Optimally Targeting the Mechanism?

Abstract

Asymptomatic hyponatremia (HN) is associated with increased mortality. Recently, an oral vasopressin receptor antagonist (tolvaptan), has been successfully used in patients with HN. In this retrospective study, tolvaptan (n=40) and a control group (n=40) were compared for HN etiology and response. Figure 1 presents are results. SIADH and CHF were the most common type of conditions that were treated with tolvaptan. The cause of HN was not clarified in 50% of the control and 10% of the tolvaptan group. In the tolvaptan group, serum sodium increased 125+4.2 mEq/L to 137+2.1 mEq/L over 5+4 days while the control group did not show any change from its baseline value of 128+4 mEq/L. The current study finds SIADH and CHF to be the main conditions where HN was treated with tolvaptan. Importantly, 50% of the control group was labeled as unclear etiology and did not receive tolvaptan. Increased awareness of the etiology and mechanisms of HN development can identify candidates suitable/unsuitable for tolvaptan.