From the Guidelines
Lidocaine infusion can potentiate the effect of non-depolarizing muscle relaxants, and its use in combination with these agents requires careful consideration and monitoring. The interaction between lidocaine and non-depolarizing muscle relaxants, such as rocuronium, vecuronium, and cisatracurium, may result in a prolonged duration of action and increased depth of neuromuscular blockade 1. When using lidocaine infusion in combination with non-depolarizing muscle relaxants, clinicians should:
- Reduce the initial dose of the muscle relaxant by 10-20%
- Monitor neuromuscular function closely using a nerve stimulator
- Be prepared for potentially delayed recovery from neuromuscular blockade The mechanism behind this interaction is thought to be related to lidocaine's ability to stabilize cell membranes and reduce acetylcholine release at the neuromuscular junction, as well as its potential to enhance the sensitivity of postjunctional nicotinic receptors to non-depolarizing agents 1. Key points to consider when using lidocaine infusion with non-depolarizing muscle relaxants include:
- The potential for increased sensitivity to non-depolarizing agents in patients with neuromuscular disease
- The need for careful monitoring of neuromuscular function to avoid overdosing
- The potential benefits of using lidocaine infusion to reduce opioid consumption and side effects in the postoperative period 1.
From the FDA Drug Label
Certain inhalation anesthetics, particularly enflurane and isoflurane, antibiotics, magnesium salts, lithium, local anesthetics, procainamide, and quinidine have been shown to increase the duration of neuromuscular block and decrease infusion requirements of neuromuscular blocking agents
- Local anesthetics have been shown to increase the duration of neuromuscular block and decrease infusion requirements of non-depolarizing muscle relaxants, such as rocuronium.
- This suggests that lidocaine infusion may potentiate the effect of non-depolarizing muscle relaxants 2.
From the Research
Interaction between Lidocaine and Non-Depolarizing Muscle Relaxants
- The effect of lidocaine on non-depolarizing muscle relaxants has been studied in several research papers 3, 4, 5.
- A study published in the European journal of pharmacology in 2010 found that lidocaine enhances the inhibitory effect of non-depolarizing muscle relaxants at adult muscle-type nicotinic acetylcholine receptors 3.
- Another study published in Anesthesia and analgesia in 1978 found that combinations of ineffective concentrations of non-depolarizing muscle relaxants and local anesthetics, including lidocaine, caused a greater than 90% neuromuscular block 4.
- However, a randomized-controlled trial published in Acta anaesthesiologica Scandinavica in 2010 found that an intravenous infusion of lidocaine did not significantly prolong the time to recovery of neuromuscular function after cisatracurium 5.
Mechanism of Interaction
- The mechanism of interaction between lidocaine and non-depolarizing muscle relaxants is thought to be due to the inhibitory effect of lidocaine on muscle-type nicotinic acetylcholine receptors 3.
- Local anesthetics, including lidocaine, may also potentiate the effect of non-depolarizing muscle relaxants by reducing the release of acetylcholine from the nerve terminal 4.
Clinical Significance
- The interaction between lidocaine and non-depolarizing muscle relaxants may be clinically significant, particularly in patients receiving high doses of both agents 4.
- However, the clinical significance of this interaction is still unclear, and further studies are needed to fully understand its effects 5.