Study of the Safety and Efficacy of Conivaptan (Vaprisol®) to Raise Serum Sodium Levels in Patients With Severe Traumatic Brain Injury

Inclusion Criteria: * 18 years old or greater * Initial diagnosis of an isolated, severe traumatic brain injury (Glasgow Coma Score of 8 or less upon initial evaluation) * Cerebral edema with a head CT and Marshall classification of diffuse injury type II, III, or IV. * Primary care team orders to raise blood sodium by 10 mEq/L from baseline. * Placement of an intraparenchymal fiberoptic monitor to monitor intracranial pressure (ICP). Exclusion Criteria: * Age \< 18 years * Signs of hypovolemia including systolic BP \< 90 mmHg * Signs of liver disease including jaundice and ascites * AST \> 35 units/L * ALT \> 35 units/L * Signs of renal disease including history of dialysis * Serum creatinine \> 1.5 mg/dL * BUN \> 20 mg/dL range * Baseline serum sodium \>/= 145 mEq/L * Pregnant or lactating females * Concomitant use of digoxin, ketoconazole, itraconazole, clarithromycin, ritonavir, indinavir, simvastatin and lovastatin * Presentation to the tertiary care hospital \> 24 hours post-injury * Multi-system traumatic injuries * Diabetes Insipidus * Anticipation of diagnosis compatible with brain death, or no expectation of survival with 48 hours.