Medications for Alzheimer's disease are used to treat dementia-related symptoms and cognitive decline. Some of them also have other uses, such as managing dementia related to Parkinson's disease. They work by increasing the levels of certain chemicals in the brain, protecting brain cells from damage, or lessening beta-amlyoid plaques. Common classes include cholinesterase inhibitors, NMDA receptor antagonists, and amyloid beta-directed antibodies. Cholinesterase inhibitors like donepezil (Aricept, Adlarity) and rivastigmine (Exelon) are usually taken as oral pills or patches. NMDA receptor antagonists, such as memantine (Namenda), are typically taken as oral pills. Combination medications like memantine/donepezil (Namzaric) are also available in oral form. Amlyoid beta-directed antibodies like donanemab (Kisunla) come as injections.