Methadone for postoperative analgesia: contribution of N-methyl-d-aspartate receptor antagonism

BACKGROUND Over the past number of years, N -methyl- d -aspartate (NMDA) inhibitory drugs, like ketamine, have been introduced as adjuvant treatments for postoperative acute pain, within a multimodal approach. A further extension of this strategy could be the use of opioids with NMDA receptor (NMDAr) antagonism activity for control of postoperative pain. Methadone has a unique pharmacodynamic profile: it is both a μ-agonist and an NMDAr-blocker....