Allopregnanolone for the Treatment of Traumatic Brain Injury

Inclusion Criteria: * English or Spanish speaking person * Moderate to severe closed or blunt traumatic brain injury \[post resuscitation Glasgow Coma Score (GCS) 3-12 with abnormal head CT scan if GCS is 9-12\] * Less than 8 hours from injury to study initiation * Able to participate for the full term of the study Exclusion Criteria: * Subjects with life expectancy of less than 24 hours * Isolated epidural hematoma * Hypoxia (pulse oximetry saturation ≤90% for 15 or more minutes before enrollment) * Hypotension (systolic blood pressure ≤90 mm Hg on 2 or more reliable measurements before enrollment) * Cardiopulmonary arrest prior to randomization * Spinal cord injury with motor deficits * Bilateral non-reactive pupils with Glasgow Coma Scale 3 * Body weight \>120 kg * Pregnancy * Active breast or reproductive organ cancer * Allergy to progesterone * History of thromboembolic events * Receipt of activated Factor VII before enrollment * Any disease that is unstable or which could jeopardize the safety of the subject including severe renal impairment (creatinine clearance \<50 ml/min) * Prisoner/ward of the state * Known treatment with another investigational drug therapy or procedure within 30 days of injury