Clinical efficacy of urea treatment in syndrome of inappropriate antidiuretic hormone secretion

The aim of this work is to examine our experience in the use of urea in patients with SIADH. Observational retrospective analysis of 48 patients with SIADH that have been treated with urea in a third-level hospital. Pre-post analysis of serum sodium levels. The 48 patients with SIADH had a median age of 78.5 (range 26–97 years). The serum sodium nadir was 119.8 ± 5.0 mmoL/L and at the beginning of treatment 125.6 ± 4.1 mmoL/L. The patients continued the treatment for a mean time of 2.95 ± 6.29 months, being the treatment still active in 4 patients. In all patients there was an improvement in serum sodium, being the final serum sodium at the end of treatment 134.4 ± 4.9 mmoL/L (p < 0.01). This improvement was observed from the first week. Adverse events were only detected in 2 patients with mild digestive symptomatology and 2 patients refused the treatment due to the low palatability of the urea. There was an economic cost reduction of 87.9% in comparison with treatment with tolvaptan. Urea has shown to be a safe and cost-effective option for the treatment of hyponatremia caused by SIADH.