Drug Interactions between doxacurium and Sensorcaine-MPF Spinal

MONITOR: Neuromuscular-blocking effects may be potentiated when neuromuscular blocking agents are coadministered with local anesthetics, however, the mechanism is not completely understood. In one study of 10 healthy volunteers evaluating the use of regional anesthesia with intravenous prilocaine with (n=5) or without mivacurium (n=5), prolonged weakness was observed in subjects who received both prilocaine and mivacurium, compared to the control group. Another study of patients undergoing orthognathic surgery (n=16) evaluated the degree of neuromuscular blockade using the train of four (TOF) prior to induction and during maintenance anesthesia with propofol, fentanyl and rocuronium, with or without an oral mucosal injection of lidocaine 1% with epinephrine 10 mcg/mL (LE). The TOF ratio began to decrease 2 minutes after the injection of LE, reached a minimum value of approximately 3% twelve minutes after the injection, and then began to recover, indicating an increase in neuromuscular blockade when LE was administered with rocuronium compared to the control group. In another study of healthy patients (n=30), the effect of epidural bupivacaine on the duration, intensity, and reversal of atracurium-induced neuromuscular muscular blockade was evaluated. In the epidural bupivacaine group (n=15), the duration of neuromuscular blockade, time until first response to TOF, and reversal time were all significantly prolonged when compared to the control group. Clinical data for all neuromuscular blocking agents and local anesthetics are lacking.

MANAGEMENT: Monitoring for prolonged and/or enhanced neuromuscular blockade is advised if local anesthetics are coadministered with neuromuscular-blocking agents. Individual product labeling for the neuromuscular blocking agent should be consulted for specific recommendations and guidance.