Mechanism of Action of Neuromuscular Blocking Agents

Depolarizing vs. Non-Depolarizing Agents

Neuromuscular blocking agents (NMBAs) play a crucial role in modern anesthesia and critical care by facilitating muscle relaxation during surgical procedures and mechanical ventilation.

Depolarizing Neuromuscular Blocking Agents

Depolarizing NMBAs, such as succinylcholine, work by mimicking acetylcholine (ACh) at the neuromuscular junction. They bind to nicotinic receptors and cause persistent depolarization, leading to muscle paralysis.

• Rapid onset of action
• Short duration
• May cause fasciculations and hyperkalemia

Non-Depolarizing Neuromuscular Blocking Agents

Non-depolarizing NMBAs, such as rocuronium and vecuronium, act by competitively inhibiting ACh at the receptor site, preventing depolarization and leading to paralysis.

• Longer duration of action
• Reversible with cholinesterase inhibitors
• Minimal systemic side effects

Clinical Applications and Considerations

These agents are used in various clinical settings, including surgery, intensive care, and emergency medicine. The choice between depolarizing and non-depolarizing NMBAs depends on factors such as onset, duration, and potential side effects.