Valproic AcId for Traumatic BRAin INjury Trial

Inclusion Criteria: 1. Male or female between the ages of 18 and 65 years. 2. Body Mass Index between 18 kg/m2 and 35 kg/m2. 3. Females must be surgically sterilized, postmenopausal, or have a negative urine pregnancy test. 4. Moderate to severe TBI: Glasgow Coma Scale (GCS) 3-12. 5. Cerebral trauma confirmed on the initial CT scan with radiographic findings consistent with Brain Injury Guidelines category 3 (BIG3) criteria Exclusion Criteria: 1. Persons with known history of adverse reactions to VPA 2. Persons with known history of hepatitis B or C or clinical history of hepatic dysfunction, pancreatitis, or renal insufficiency. 3. Persons with a known history of thrombocytopenia. 4. Persons with platelet count less than 100,000 per microliter of blood. 5. Persons with 2nd or 3rd degree burns of any size and location. 6. Female subjects who are pregnant or lactating. 7. Persons who are currently incarcerated or are in police custody. 8. Persons with inadequate venous access. 9. Treatment cannot start within 120 minutes from the onset of injury 10. Non-survivable injuries in the estimation of the attending trauma surgeon. 11. Interfacility transfers 12. The time of injury is unknown 13. Patients in hemorrhagic shock with a systolic blood pressure of \<90 mmHg on initial evaluation. 14. Persons with a known "do not resuscitate" order prior to randomization 15. Persons with a research "opt out" bracelet 16. Persons who are currently enrolled in another clinical trial. 17. Greater than 90 minutes between the onset of injury and arrival to the hospital