ketamine + lidocaine + methadone

This is a compounded combination of three drugs—ketamine, lidocaine, and methadone—used primarily for analgesia in perioperative or critical care settings. Each component has a distinct mechanism of action: - **Ketamine** is a dissociative anesthetic that acts as an antagonist at the N-methyl-D-aspartate (NMDA) receptor, providing analgesic effects and reducing central sensitization to pain. - **Lidocaine** is an amide-type local anesthetic that blocks voltage-gated sodium channels on neuronal membranes, inhibiting nerve impulse conduction and thus providing local or systemic analgesia. - **Methadone** is a synthetic opioid agonist with activity at the mu-opioid receptor; it also antagonizes NMDA receptors and inhibits serotonin/norepinephrine reuptake, contributing to its unique profile for both acute and chronic pain management. This combination is not marketed under a proprietary brand name but may be prepared in hospital pharmacies for intravenous infusion. It has been studied for stability in various diluents (e.g., 0.9% NaCl or Hartmann's solution), showing acceptable chemical stability (<10% degradation) for up to 48 hours post-preparation[1][3]. The mixture provides multimodal analgesia by targeting different pathways involved in pain transmission[6].