Ketamine Preemptive Analgesia is an antinociceptive treatment targeted to block CNS hyperexcitability, and thereby leads to a reduced postoperative pain state.
Excitatory amino acids aspartate, released by the C fibers, interacts with the NMDA receptors of the dorsal horn neurons, and thus, leads to increase in intracellular calcium ions, which is thought to be the predominant mechanism behind persistent, abnormal neuronal hypersensitivity following noxious stimuli.
Ketamine Preemptive Analgesia by antagonizing the NMDA receptors prevents central sensitization.
Intravenous low-dose (0.15 mg/kg) ketamine can produce preemptive effect and decreases postoperative opioid consumption. Argiriadou et al. have shown that after major visceral surgery, preincisional and repeated intraoperative small-dose S(+)-ketamine added to general and epidural anaesthesia causes better postoperative pain relief than general and epidural anaesthesia alone.