Abstract: NMDA receptor blockers, including pH-sensitive NMDA receptor blockers, are provided as neuroprotective drugs that are useful in stroke, traumatic brain injury, epilepsy, and other neurologic events that involve acidification of brain or spinal cord tissue. Compositions and methods of this invention are used for treating neurodegeneration resulting from NMDA receptor activation. The compounds described herein have enhanced activity in brain tissue having lower-than normal pH due to pathological conditions such as hypoxia resulting from stroke, traumatic brain injury, global ischemia tat may occur during cardiac surgery, hypoxia tat may occur following cessation of breathing, pre-eclampsia, spinal cord trauma, epilepsy, chronic pain, vascular dementia and glioma tumors.