Disclosed herein are non-competitive NMDA receptor antagonists having chemical structures similar to that of phencyclidine (PCP). These antagonists contain a polycyclic ring structure in place of the cycloalkyl ring of PCP. The antagonists also differ from PCP in that they include an electron withdrawing group, a hydroxyl group, or an amine group at the para position of the phenyl ring. The antagonists disclosed herein are useful for treating or ameliorating a symptom of ailments associated with over excitation of cells (e.g., neurons) that express NMDA receptors. Examples of ailments that can be treated and for which symptoms can be ameliorated include epilepsy, neurodegenerative disease (e.g., Alzheimers and Parkinsons diseases), drug addiction, neuropathic pain, and neuronal and glutamate-dependent tumors.