Ketamine is an anti-N-methyl-D-aspartate (NMDA) medication. It is supposed to limit excitotoxicity of amino-acids, especially glutamate. Glutamate is known to be elevated in more than 60% of the severe head trauma patients. It induces cortical spreading depression which can aggravate prognosis. It's a daily used medication in anesthesia and intensive care units for sedation and induction of anesthesia. It's the recommended medication for induction of unstable wounded soldiers on the field because of its neutrality on haemodynamic state.