Post-traumatic seizures can appear frequently after a severe traumatic brain injury. Two types of seizures are usually identified: early seizures during the week following the trauma and late epilepsy afterward. Several antiepileptic drugs are usually used to prevent early seizures but no treatment has demonstrated any preventive effect against late epilepsy. Levetiracetam is an antiepileptic drug usually used for the treatment of epileptic patients and has pharmacologic properties that could also be interesting for the prevention of post-traumatic epilepsy.

• Drug: Levetiracetam
• Drug: Placebo

Inclusion Criteria:

1. Age >= 18 years old

2. Patient with severe brain injury defined as follow:

   • Initial Glasgow Coma score (assessed on the scene of the accident) <= 8 related to the brain injury
   • Stage 2 to 4 on the TDM US TCDB classification
3. Initial brain CT scan performed within 48 hours after hospital admission
4. Either a male or a nonpregnant, non-lactating female who is using adequate contraceptive method (a urine laboratory pregnancy test must be negative at baseline)
5. Written informed consent from the patient's next-of-kin. If no relative is present as the time of inclusion, the patients will be included according to the emergency procedure

Exclusion Criteria:

1. Isolated extradural hematoma
2. Medical decision to limit patient's care (terminal stage of a cancer, hematological malignancies, HIV, etc.)
3. Current participation in an other protocol or within one month before study entry
4. Previous treatment with Levetiracetam
5. Patient's follow-up judged to be difficult by the investigator
6. Known allergy to either Levetiracetam or products derived from pyrrolidone or one of its excipients
7. Epileptic patient treated or not (except patients treated with benzodiazepines who can be included in this protocol)