Purpose: Tolvaptan, a vasopressin receptor antagonist has been accepted as a therapeutic alternative for refractory hyponatremia treatment in heart failure (HF) patients. We aimed to assess differences in Tolvaptan response according to renal function.
Methods: We reviewed data from all patients admitted for HF and refractory hyponatremia (Na <135 mEq/L despite fluid restriction and/or hypertonic saline) treated with Tolvaptan. Patients were divided in two groups according to their glomerular filtration rate [MDRD (mL/min/1,73m2)] at the moment of receiving Tolvaptan (group A <60 and B >60). Na, potassium [K (mEq/L)], creatinine [Cr (mg/dL)] and MDRD, diuresis (mL/h), blood pressure (mmHg) and weight (kg) were evaluated at administration, 24 and 48 hours after.
Results: 35 patients were included (25 in A and 10 in B). Baseline characteristics are shown in table 1. Plasma Na was lower in B (128 ± 4 vs 130 ± 3 in A) with a significant increase in both groups at 24 (134 ± 2 in A vs 134 ± 5 in B) and 48 hours (135 ± 3 in A vs 136 ± 3 in B). Diuresis increased significantly in both groups at 24 hours (273 (95% CI 40-505) in A and 227 (95% CI 120-334) in B) which correlated with a corresponding significant weight loss in group B. We found no changes in K, Cr, MDRD or blood pressure.
Conclusions: In our experience, Tolvaptan was safe and effective in increasing sodium plasma level and diuresis regardless the renal renal function.