Efficacy, Efficiency and Security of Urea Treatment in the Syndrome of Inappropiate Antidiuretic Hormone Secretion

Introduction: In the present times, several strategies have been proposed for the treatment of the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Urea has demonstrated to be an effective treatment but its use has not been extended. Our work analyzes our experience with urea in the treatment of SIADH. Material and Methods: Observational retrospective analysis of 39 patients with SIADH in which urea has been used in our hospital with pre- and post-analysis of plasmatic sodium concentrations. Results: We included 39 patients with SIADH win a mean age of 76,4 ± 15,8 years. The plasma sodium nadir was 120,0 ± 5,1 mmoL/L and at the initiation of treatment 125,2 ± 4,1 mmoL/L. Total time of treatment was 2,42 ± 3,86 months being the treatment still active in 4 patients. We observed an improvement of sodium in all patients with a mean sodium at the end of treatment of 134.3 + - 5.0 mmol/L being this values statistically significant compared to the initial sodium (p<0.01). As a matter of fact we found significant differences at one week of treatment (p<0.01), keeping sodium stable levels around 135 mmol/L during the treatment period. The treatment was stopped in 3 cases (7.7 %) by the patient, one for mild digestive symptomatology and two for limited palatability. Of them two were treated with tolvaptan and the other did not need any further treatment. There were no adverse events in the rest of the patients. From the economic perspective and considering the duration of treatment, if we compare this to the cost of tolvaptan during the same period and the same number of patients, there was a reduction of cost of 87.9 % in comparison with treatment with tolvaptan. Conclusions: In our experience urea has shown to be a safe and cost effective option in the treatment of hyponatremia caused by SIADH showing improvement in sodium levels from the first week of treatment in all patients. We think it should be considered a valid therapeutic option.