Purpose: The long-term efficacy of tolvaptan, a vasopressin V2 receptor antagonist, has been reported. However, the safety of long-term treatment remains to be fully elucidated. We assessed the safety profile of tolvaptan with respect to hypernatremia.
Methods: This retrospective study included 371 patients treated with tolvaptan. Risk factors for hypernatremia (serum sodium concentration ≥147 mEq/L) were determined.
Results: Hypernatremia occurred in 95 patients (25.6 %), of whom 71 (19.1 %) developed hypernatremia within 7 days of tolvaptan treatment (early onset). Stepwise logistic regression analysis demonstrated that baseline serum sodium ≥140 mEq/L, an initial tolvaptan dosage >7.5 mg, and a BUN/serum creatinine ratio ≥20 were independent risk factors for early onset of hypernatremia. Tolvaptan was prescribed for more than 7 days to 233 patients, of whom 123 were administrated tolvaptan for more than 1 month. Hypernatremia occurred in 24 of these patients (10.3 %) (late onset). Predictive factors for late onset of hypernatremia were an average daily dosage of tolvaptan >7.5 mg and age ≥75 years.
Conclusions: A daily dosage of 7.5 mg or less was recommended to prevent hypernatremia in short- as well as long-term tolvaptan treatment, and mainly elderly patients were at risk for hypernatremia.
Keywords: Diuretics; Heart failure; Hypernatremia; Liver cirrhosis; Tolvaptan.