Currently, there are no United States Food and Drug Administration (FDA)-approved pharmaceuticals for the treatment of TBI. Pathologically, TBI follows a biphasic pattern consisting of the primary structural injury followed by a secondary injury cascade. Primary injuries include cerebral contusion, blood vessel damage, blood brain barrier disruption, axonal shearing, and neuronal apoptosis. The secondary injury cascade includes inflammation, edema, changes in cerebral circulation, glutamate toxicity, mitochondrial dysfunction, and increased reactive oxygen species (ROS) production. In 2019, the FDA fast-tracked NeuroSTAT (cyclosporine; NeuroVive Pharmaceutical) for the treatment of moderate-to-severe TBI by inhibiting mitochondrial permeability transition pore (mPTP), which is indicated in the secondary injury cascade
[46]. Notably, if approved, this treatment will only be effective during the early acute injury phase. Amantadine is safe and has shown some accelerated recovery in studies of acute and subacute DoCs due to TBI
[47][48][49], but with variable effectiveness
[50][51]. Like amantadine, apomorphine has effects on the dopaminergic system. A case study and a pilot study with apomorphine described a spontaneous awakening phenomenon
[52][53], and a controlled study has been proposed to evaluate its safety and effectiveness
[54]. During the chronic phase post-TBI, case reports on zolpidem have indicated a paradoxical ability to improve consciousness
[55][56]. An EEG study suggested it acts on cortical, striatal, and thalamic neuronal populations to potentially produce this spontaneous awakening phenomenon
[57]. Controlled studies have shown zolpidem to be safe, but again showed variable effectiveness
[58][59][60][61]. Lorazepam was also shown to be safe, albeit ineffective in a single study for TBI, but showed some effectiveness for patients with anoxic brain injury
[61]. Together, these results suggest potential pharmaceutical options for acute, subacute, and chronic DoCs, with reasonable safety profiles but variable effectiveness.