Current Alzheimer’s drugs support brain processes
through two different mechanisms:
1) Cholinesterase inhibitors work by slowing down the process that breaks down a key neurotransmitter. Donepezil, galantamine and rivastigmine are cholinesterase inhibitors.
2) Memantine, the fifth Alzheimer’s drug, is an NMDA (N-methyl-D-aspartate) receptor antagonist, which works by regulating the activity of glutamate, an important neurotransmitter in the brain involved in learning and memory. Attachment of glutamate to cell surface “docking sites” called NMDA receptors permits calcium to enter the cell. This process is important for cell signaling, as well as learning and memory. In Alzheimer’s disease, however, excess glutamate can be released from damaged cells, leading to chronic overexposure to calcium, which can speed up cell damage. Memantine helps prevent this destructive chain of events by partially blocking the NMDA receptors.
The effectiveness of cholinesterase inhibitors and memantine varies across the population.