Memantine is a medication primarily used to treat moderate to severe Alzheimer's disease. It works by regulating the activity of glutamate, a neurotransmitter in the brain that is involved in learning and memory. By blocking excessive glutamate activity, memantine helps to protect brain cells and may improve cognitive function in some patients. This drug is usually prescribed when other treatments, such as cholinesterase inhibitors, are not effective or suitable. Memantine can help manage symptoms but does not cure Alzheimer's disease. It is typically taken as a tablet or liquid and may have side effects, including dizziness and confusion.