Roger F Butterworth
Results of a systematic review with meta-analysis of 30 RCTs confirm the efficacy and safety of memantine when used as monotherapy or in combination with cholinesterase inhibitors for the treatment of AD where both cognitive function and behavioural disturbance scores were significantly improved. FDA approval was subsequently granted for the treatment of moderate-to-severe AD. Mechanisms responsible for these beneficial effects include memantine’s property as a non-competitive, low affinity, open-channel blocker of the NMDA receptor and its associated ion channel. An alternative explanation has emerged based upon the discovery that astroglia and microglia play a key role in the pathogenesis of neurodegenerative diseases together with reports of memantine’s ability to control microglial activation and its associated anti-inflammatory response occurring independent of NMDA receptors. Additionally, by virtue of its established antiviral properties, memantine has also been proposed for the treatment of a number of neurodegenerative disorders with associated viral etiology. Neurodegenerative diseases including AD are considered to be co-morbidities of concern during the COVID-19 pandemic. In vitro studies confirm a beneficial effect of memantine against the E protein of SARS-Co-V-2 and a cohort of patients with severe cognitive impairment treated long-term with memantine developed no signs of infectious disease following PCR-confirmed infection with COVID-19 while memantine-related improvements in neurologic status were maintained