ACHE and Alzheimer disease: There are currently six FDA-approved drugs for the treatment of AD, four of which (tacrine, donepezil, rivastigmine, and galantamine) are acetylcholinesterase inhibitors, and one of which (memantine) is a NMDA antagonist, while aducanumab is an amyloid beta-directed monoclonal antibody (Jurcau 2021).