Memantine. Computer model of a molecule of the Alzheimer's drug memantine. Atoms are represented as spheres and are colour-coded: carbon (green), hydrogen (white) and nitrogen (blue). Memantine belongs to a class of drugs known as NMDA receptor antagonists. It binds to the same sites in the brain as the neurotransmitter glutamate. Glutamate is over-produced in patient's with Alzheimer's disease, a common cause of dementia in the elderly, leading to a large influx of calcium into brain cells. The calcium damages the cells, causing the symptoms of dementia. Memantine does not cure the disease, but it does slow its progression and improve cognitive function and the ability to carry out everyday tasks.