ondansetron + lidocaine

A combination of ondansetron and lidocaine used primarily in intravenous regional anesthesia (IVRA) procedures. When ondansetron (typically 8 mg) is added to lidocaine for IVRA, it has been shown to reduce both intraoperative and postoperative analgesic requirements for up to 24 hours after surgery. The combination produces faster onset of sensory and motor blocks and prolongs the recovery time of these blocks compared to lidocaine alone. Ondansetron possesses analgesic properties by blocking sodium channels (similar to local anesthetics but approximately fifteen times more potent than lidocaine) and may act as an opioid agonist by binding to opioid mu receptors, producing peripheral nociceptive analgesic effects.