donepezil + galantamine + memantine + rivastigmine

This is a combination of four drugs—donepezil, galantamine, rivastigmine, and memantine—used in the management of Alzheimer's disease. Donepezil, galantamine, and rivastigmine are acetylcholinesterase inhibitors that work by preventing the breakdown of acetylcholine in the brain, thereby enhancing cholinergic neurotransmission. Memantine is an NMDA receptor antagonist that protects neurons from glutamate-mediated excitotoxicity. While each drug individually or in dual combinations (such as a cholinesterase inhibitor plus memantine) has been studied and used clinically for Alzheimer's disease, there is no evidence or clinical guideline supporting the simultaneous use of all four agents together. The combination would theoretically target both cholinergic and glutamatergic pathways implicated in Alzheimer's pathology[2][3][4][5][7]. However, such quadruple therapy is not standard practice due to overlapping mechanisms among the three cholinesterase inhibitors and potential for increased adverse effects.