Amantadine and Modafinil as Neurostimulants During Post-stroke Care: A Systematic Review

Amantadine and modafinil are neurostimulants that may improve cognitive and functional recovery post-stroke, but the existing study results vary, and no comprehensive review has been published. This systematic review describes amantadine and modafinil administration practices post-stroke, evaluates timing and impact on clinical effectiveness measures, and identifies the incidence of potential adverse drug effects. A librarian-assisted search of the MEDLINE (PubMed) and EMBASE databases identified all English-language publications with "amantadine" or "modafinil" in the title or abstract from inception through February 1, 2020. Publications meeting predefined Patient, Intervention, Comparator, Outcome (PICO) criteria were included: Patients (≥ 18 years of age post-stroke); Intervention (amantadine or modafinil administration); Comparison (pretreatment baseline or control group); Outcomes (cognitive or functional outcome). Amantadine and modafinil administration practices, cognitive and functional outcomes, and incidence of potential adverse drug effects were collected following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidance. Quantitative analyses were not performed due to heterogeneity in the clinical effectiveness measures; descriptive data are presented as number (percent) or median (interquartile range). Of 12,620 publications initially identified, 10 amantadine publications (n = 121 patients) and 12 modafinil publications (n = 120 patients) were included. Amantadine was initiated 39 (16, 385) days post-stroke, with most common initial doses of 100 mg once or twice daily (range 100-200 mg/day), and final daily dose of 200 (188, 200) mg/day. Modafinil was initiated 170 (17, 496) days post-stroke, with initial and final daily doses of 100 (100, 350) mg/day and 200 (100, 350) mg/day, respectively. The most common indication was consciousness disorders for amantadine (n = 3/10 publications; 30%) and fatigue for modafinil (n = 5/12; 42%). Forty unique clinical effectiveness measures (1.8 per study) with 141 domains (6.4 per study) were described across all studies. A positive response in at least one clinical effectiveness measure was reported in 70% of amantadine publications and 83% of modafinil publications. Only one publication each for amantadine (10%; n = 5 patients) and modafinil (8%; n = 21 patients) studied acutely hospitalized or ICU patients; both were randomized studies showing improvements in neurocognitive function for amantadine and fatigue for modafinil. Potential adverse drug effects were reported in approximately 50% of publications, most commonly visual hallucinations with amantadine (2% of patients) and dizziness (5% of patients) and dry eyes or mouth (5% of patients). Amantadine and modafinil may improve cognitive and functional recovery post-stroke, but higher-quality data are needed to confirm this conclusion, especially in the acute care setting.