The Effect of Amantadine Use on the Outcome of the Patients with Traumatic Brain Injury

Aim. To evaluate whether amantadine use improves the outcome of adult patients with moderate and severe brain injury. Objectives. To determine the optimal duration, time, and dose of amantadine administration based on selected articles in the databases. To evaluate the effects of amantadine in patients with traumatic brain injury in the acute and subacute post-traumatic period. To assess the impact of amantadine use on the longterm outcomes in patients with traumatic brain injury. Method. To identify studies describing the effects of amantadine on the outcome of patients with traumatic brain injury, a search was conducted in the databases of PubMed, Cochrane, and EBSCO. Only the studies published till January 1, 2020 in English language were included in the search. The search was performed using the keywords "traumatic brain injury", "amantadine", "outcome". A total of 158 articles were found for the search query. The primary selection was made based on the study title and summary. The selected full-text articles were screened and examined according to the selection criteria: randomized, placebo-controlled, double-blind clinical trial, published in a peer-reviewed scientific journal, analyzing the administration of amantadine effect to improve the state of consciousness of patients with moderate and severe brain injury. Results. Of the 158 identified articles in English, 5 clinical trials were included in the systematic literature review. A total of 359 patients with moderate or severe brain injury participated in the studies. Amantadine was administered to 192 patients and placebo to 167 patients. The outcomes of the patients were assessed using the GCS (Glasgow Coma Scale), DRS (Disability Rating Scale), GOS (Glasgow Outcome Scale), KPS (Karnofsky Performance Status) scales, and the number of deaths. The majority of studies showed a significantly faster recovery in the amantadine group during the treatment period, but after discontinuation of the drug the rate of recovery decreased and there was no statistically significant difference in the long-term outcome between patients in the amantadine and placebo groups. Conclusions. Amantadine is more commonly given in the subacute period (> 4 weeks after injury). The most commonly used oral dose is 200 mg daily. The duration of amantadine use is 4-6 weeks. Amantadine improved the rate of recovery of consciousness in the first days of treatment, but this effect disappeared upon discontinuation. The drug had no effect on long-term outcomes compared to placebo