From the Guidelines
Amantadine should be considered for use in patients after traumatic brain injury to promote consciousness recovery, as evidenced by its safety and possible efficacy in similar conditions such as aneurysmal subarachnoid hemorrhage. The use of amantadine in this context is supported by a systematic review that included 20 retrospective studies, with 10 studies specifically examining the use of amantadine in patients with severe acute brain injuries, including traumatic brain injury 1. Although the evidence is not specific to traumatic brain injury, it can be extrapolated from the literature on aneurysmal subarachnoid hemorrhage, which suggests that neurostimulants like amantadine may be initiated safely in the subacute period to promote consciousness recovery.
Some key points to consider when using amantadine in patients after traumatic brain injury include:
- The median time from injury to initiation of neurostimulants was approximately 19 days, suggesting that amantadine may be started in the subacute period 1
- The dose and duration of amantadine treatment may vary depending on patient response and tolerance, but typical dosing regimens start at 100mg once or twice daily
- Amantadine works by enhancing dopaminergic neurotransmission in the brain, which may help improve attention, concentration, and processing speed in patients with traumatic brain injury
- Common side effects of amantadine include insomnia, anxiety, dizziness, and hallucinations, and the medication should be used cautiously in patients with seizure disorders, psychiatric conditions, or cardiovascular disease
Overall, while the evidence is not yet definitive, amantadine may be a useful adjunctive treatment for patients after traumatic brain injury, particularly those with disorders of consciousness or slow neurological recovery, and its use should be considered on a case-by-case basis, taking into account the individual patient's needs and medical history 1.
From the Research
Role of Amantadine in Treating Patients after Traumatic Brain Injury
- Amantadine, an antiviral and antiparkinsonian medication, has been studied for its potential role in improving cognitive function in patients after traumatic brain injury (TBI) 2, 3, 4, 5, 6.
- A meta-analysis found that amantadine significantly enhanced cognitive function in patients with TBI, with a mean difference of 0.50 (95% CI, 0.33-0.66; p < 0.001) 2.
- The effects of amantadine on TBI outcome have been investigated in several studies, with some finding improvements in cognitive function, particularly when started early after injury 2, 4, 5.
- A double-blind, randomized, controlled clinical trial found that amantadine did not lead to significant effects on patients' level of consciousness, memory, disability, cognition, mortality, and performance 3.
- Amantadine has been found to be well-tolerated, with a low incidence of severe adverse events, such as seizures, elevation in liver enzymes, and cardiac death 5.
Timing and Duration of Amantadine Treatment
- Starting amantadine in the first week after TBI has been found to have a significant effect on improving cognitive function (MD, 0.97; 95% CI, 0.45-1.49) 2.
- Amantadine administered for less than 1 month has been found to have a better effect on cognitive function (MD, 0.83; 95% CI, 0.56-1.11) 2.
- The optimal duration of amantadine treatment is not well-defined, with some studies finding benefits in the intermediate-term outcome (four to six weeks after end of treatment) 5.
Patient Characteristics and Response to Amantadine
- Amantadine has been found to have a better effect on cognitive function in patients below 18 years of age (MD, 0.66; 95% CI, 0.32-0.99) and in patients with less severe TBI (MD, 0.40; 95% CI, 0.18-0.62) 2.
- The response to amantadine may vary depending on individual patient characteristics, such as age, severity of injury, and time since injury 2, 4, 5.