Urea on par with tolvaptan for hyponatremia

Urea is as effective as tolvaptan in the treatment of hyponatremia, with a lower incidence of overcorrection, as shown in a study.

“The effectiveness of the vasopressin receptor antagonist tolvaptan on serum sodium normalization has been well described in the literature, although the associated risk of serum sodium overcorrection limits its use,” the authors said. 

“Urea has been proposed as an alternative treatment option due to its milder serum sodium raising effects and adverse event profile,” they added.

In this multicentre retrospective review, the authors included 46 hospitalized patients who received either urea or tolvaptan for the management of hyponatremia. They assessed the participants to determine the rate of serum sodium normalization and overcorrection.

At baseline, the mean serum sodium concentrations were 125.91 mEq/L for patients who received urea and 123.83 mEq/L for those treated with tolvaptan. After 12 hours, tolvaptan use resulted in a markedly higher rate of serum sodium increase relative to urea (5.05 vs 1.10 mEq/L; p=0.001).

However, no statistically significant differences were seen in the mean change in serum sodium concentration at 24 and 48 hours or with the number of patients who reached a serum sodium concentration of 135 mEq/L between the two treatment groups.

Notably, overcorrection of hyponatremia occurred more frequently in the tolvaptan group than in the urea group (43 percent vs 9 percent).

"The results of this study suggest that urea has a comparable effectiveness profile to tolvaptan for the management of hyponatremia with a significantly reduced risk of overcorrection,” the authors said.