Safety and Efficacy of Tolvaptan for Acute Refractive Hyponatremia Associated with Traumatic Brain Injury

<b>Background:</b> Hyponatremia, defined as a serum sodium concentration below 135 mmol/L, is a common and serious electrolyte disturbance in patients with traumatic brain injury (TBI), and may be treated with vaptans-vasopressin receptor antagonists that promote water excretion. This study evaluates the safety and efficacy of tolvaptan, a vaptan, in correcting hyponatremia in TBI patients compared to a non-trauma cohort. <b>Methods:</b> We conducted a single-center retrospective analysis of 126 adult patients in the intensive care unit who received tolvaptan. The study included 73 TBI patients and 53 non-trauma patients with chronic medical conditions. Serum sodium levels were assessed 48 h after tolvaptan administration and compared between the two groups. <b>Results:</b> At baseline, the mean sodium level was higher in the TBI group compared to the non-trauma group (128.3 ± 4 mmol/L vs. 125.3 ± 5 mmol/L, <i>p</i> = 0.003). Both groups showed a significant increase in sodium levels after 48 h of tolvaptan therapy, and while the post-treatment sodium level was higher in the TBI group, the absolute change was not significantly different between the two groups (132.3 ± 5 mmol/L vs. 130.9 ± 7 mmol/L, <i>p</i> = 0.18). Sodium normalization (135-145 mmol/L) occurred in 48% of TBI patients versus 30% of non-trauma patients (<i>p</i> = 0.045), though this difference was not statistically significant after adjusting for baseline sodium levels. No cases of osmotic demyelination syndrome were observed. <b>Conclusions:</b> Our preliminary analysis suggests that tolvaptan effectively increases sodium levels in both TBI and non-trauma patients with hyponatremia. Further research is needed to fully characterize this response and determine the optimal use of tolvaptan for managing hyponatremia in the TBI population.