Browsing by Subject "Amantadine"

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    Amantadine Did Not Positively Impact Cognition in Chronic Traumatic Brain Injury: A Multi-Site, Randomized, Controlled Trial
    (Mary Ann Liebert, 2018-10-01) Hammond, Flora M.; Sherer, Mark; Malec, James F.; Zafonte, Ross D.; Dikmen, Sureyya; Bogner, Jennifer; Bell, Kathleen R.; Barber, Jason; Temkin, Nancy; Physical Medicine and Rehabilitation, School of Medicine
    Despite limited evidence to support the use of amantadine to enhance cognitive function after traumatic brain injury (TBI), the clinical use for this purpose is highly prevalent and is often based on inferred belief systems. The aim of this study was to assess effect of amantadine on cognition among individuals with a history of TBI and behavioral disturbance using a parallel-group, randomized, double-blind, placebo-controlled trial of amantadine 100 mg twice-daily versus placebo for 60 days. Included in the study were 119 individuals with two or more neuropsychological measures greater than 1 standard deviation below normative means from a larger study of 168 individuals with chronic TBI (>6 months post-injury) and irritability. Cognitive function was measured at treatment days 0, 28, and 60 with a battery of neuropsychological tests. Composite indices were generated: General Cognitive Index (included all measures), a Learning Memory Index (learning/memory measures), and Attention/Processing Speed Index (attention and executive function measures). Repeated-measures analysis of variance revealed statistically significant between-group differences favoring the placebo group at day 28 for General Cognitive Index (p = 0.002) and Learning Memory Index (p = 0.001), but not Attention/Processing Speed Index (p = 0.25), whereas no statistically significant between-group differences were found at day 60. There were no statistically significant between-group differences on adverse events. Cognitive function in individuals with chronic TBI is not improved by amantadine 100 mg twice-daily. In the first 28 days of use, amantadine may impede cognitive processing. However, the effect size was small and mean scores for both groups were generally within expectations for persons with history of complicated mild-to-severe TBI, suggesting that changes observed across assessments may not have functional significance. The use of amantadine to enhance cognitive function is not supported by these findings.
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    Amantadine effect on perceptions of irritability after traumatic brain injury: results of the amantadine irritability multisite study
    (Mary Ann Liebert, Inc., 2015-08-15) Hammond, Flora M.; Sherer, Mark; Malec, James F.; Zafonte, Ross D.; Whitney, Marybeth; Bell, Kathleen; Dikmen, Sureyya; Bogner, Jennifer; Mysiw, Jerry; Pershad, Rashmi; Physical Medicine and Rehabilitation, School of Medicine
    This study examines the effect of amantadine on irritability in persons in the post-acute period after traumatic brain injury (TBI). There were 168 persons ≥6 months post-TBI with irritability who were enrolled in a parallel-group, randomized, double-blind, placebo-controlled trial receiving either amantadine 100 mg twice daily or equivalent placebo for 60 days. Subjects were assessed at baseline and days 28 (primary end-point) and 60 of treatment using observer-rated and participant-rated Neuropsychiatric Inventory (NPI-I) Most Problematic item (primary outcome), NPI Most Aberrant item, and NPI-I Distress Scores, as well as physician-rated Clinical Global Impressions (CGI) scale. Observer ratings between the two groups were not statistically significantly different at day 28 or 60; however, observers rated the majority in both groups as having improved at both intervals. Participant ratings for day 60 demonstrated improvements in both groups with greater improvement in the amantadine group on NPI-I Most Problematic (p<0.04) and NPI-I Distress (p<0.04). These results were not significant with correction for multiple comparisons. CGI demonstrated greater improvement for amantadine than the placebo group (p<0.04). Adverse event occurrence did not differ between the two groups. While observers in both groups reported large improvements, significant group differences were not found for the primary outcome (observer ratings) at either day 28 or 60. This large placebo or nonspecific effect may have masked detection of a treatment effect. The result of this study of amantadine 100 mg every morning and noon to reduce irritability was not positive from the observer perspective, although there are indications of improvement at day 60 from the perspective of persons with TBI and clinicians that may warrant further investigation.
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    N-methyl D-aspartate (NMDA) receptor antagonists and memantine treatment for Alzheimer's disease, vascular dementia and Parkinson's disease
    (Bentham Science Publishers, 2012-07) Olivares, David; Deshpande, Varun K.; Shi, Ying; Lahiri, Debomoy K.; Greig, Nigel H.; Rogers, Jack T.; Huang, Xudong; Department of Psychiatry, IU School of Medicine
    Memantine, a partial antagonist of N-methyl-D-aspartate receptor (NMDAR), approved for moderate to severe Alzheimer's disease (AD) treatment within the U.S. and Europe under brand name Namenda (Forest), Axura and Akatinol (Merz), and Ebixa and Abixa (Lundbeck), may have potential in alleviating additional neurological conditions, such as vascular dementia (VD) and Parkinson's disease (PD). In various animal models, memantine has been reported to be a neuroprotective agent that positively impacts both neurodegenerative and vascular processes. While excessive levels of glutamate result in neurotoxicity, in part through the over-activation of NMDARs, memantine-as a partial NMDAR antagonist, blocks the NMDA glutamate receptors to normalize the glutamatergic system and ameliorate cognitive and memory deficits. The key to memantine's therapeutic action lies in its uncompetitive binding to the NMDAR through which low affinity and rapid off-rate kinetics of memantine at the level of the NMDAR-channel preserves the physiological function of the receptor, underpinning memantine's tolerability and low adverse event profile. As the biochemical pathways evoked by NMDAR antagonism also play a role in PD and since no other drug is sufficiently effective to substitute for the first-line treatment of L-dopa despite its side effects, memantine may be useful in PD treatment with possibly fewer side effects. In spite of the relative modest nature of its adverse effects, memantine has been shown to provide only a moderate decrease in clinical deterioration in AD and VD, and hence efforts are being undertaken in the design of new and more potent memantine-based drugs to hopefully provide greater efficacy.