NMDA receptors play an important role in processes like memory, learning, and synaptic plasticity. Drugs can act on NMDA receptors by blocking the receptor channel, competitively inhibiting glutamate or glycine binding sites, or through non-competitive mechanisms. Common NMDA receptor antagonists discussed include ketamine, memantine, and dizocilpine. Newer drugs targeting NMDA receptors are being investigated for neurodegenerative diseases, psychiatric conditions, and pain.