neuroprotectants

Neuroprotectants are therapeutic agents intended to preserve neuronal structure and function during and after neurological injury or disease. The term encompasses drugs used in acute settings such as stroke and traumatic brain injury, as well as experimental strategies aimed at slowing progression in neurodegenerative conditions. Neuroprotection is distinct from neurorestoration, which seeks to repair damaged neural tissue after injury.

Most neuroprotectants act by countering core pathogenic processes, including excitotoxicity from excessive glutamate, oxidative stress, inflammation, and mitochondrial dysfunction. They may stabilize cells and organelles, preserve energy production, modulate calcium influx, reinforce the blood-brain barrier, or interfere with apoptotic signaling. Timing and dosing are critical, as injury evolves through multiple phases.

Representative agents and notes: Edaravone is a free radical scavenger approved for amyotrophic lateral sclerosis in the United States and used for acute ischemic stroke in some countries. Nimodipine, a calcium channel blocker, is used to reduce vasospasm after subarachnoid hemorrhage. Memantine, an NMDA receptor antagonist, is approved for Alzheimer's disease and studied for broader neuroprotection. Minocycline has anti-inflammatory and anti-apoptotic effects investigated in stroke and traumatic brain injury. N-acetylcysteine, a glutathione precursor, and CDP-choline (citicoline) have been studied for neuroprotection with mixed results.

Clinical translational challenges are substantial. Many agents show benefit in preclinical models but fail to improve functional outcomes in large randomized trials. Variability in injury type and timing, publication bias, and safety concerns contribute to the lack of a universal neuroprotectant.

In practice, neuroprotectants are used in specific contexts (for example, nimodipine after subarachnoid hemorrhage) and as topics of ongoing investigation in stroke, traumatic brain injury, spinal cord injury, and neurodegenerative disorders. The field continues to explore safer, more effective strategies to blunt early injury and support recovery.