- Rocuronium:
- Mechanism: Non-depolarizing neuromuscular blocker that competitively inhibits acetylcholine at the nicotinic receptors, preventing muscle contraction.
- Uses: Rapid sequence intubation (RSI), general anesthesia maintenance.
- Best for: Patients needing prolonged muscle relaxation without the risks of depolarizing agents.
- Special considerations: Steroid based. Longer onset than succinylcholine but fewer contraindications. Also longer acting. Can be reversed with Sugammadex.
- Population/Clinical Use: Ideal for intubation in patients with hyperkalemia, burns, neuromuscular disorders, or contraindications to succinylcholine.
- Succinylcholine:
- Mechanism: Depolarizing neuromuscular blocker that binds to nicotinic receptors, causing sustained depolarization and muscle paralysis.
- Uses: Gold standard for rapid sequence intubation (RSI) due to rapid onset and short duration.
- Best for: Emergency intubation where quick onset and offset are needed.
- Special considerations: Causes fasciculations, hyperkalemia, malignant hyperthermia, and bradycardia in some cases. Has a short duration of action.
- Population/Clinical Use: Used in emergency settings, trauma, and C-sections. Avoid in burn patients, neuromuscular disease, severe hyperkalemia.
- Difference Between Depolarizing and Non-depolarizing neuromuscular blockers:
- Depolarizing muscarinic blockers cause prolonged stimulation of the nicotinic receptors, which leads to continuous stimulation of the muscle. Think of your own muscles – if you use them for a long time, you will get tired and it will stop contracting (this is why they cause fasciculations when first given). Non-depolarizing muscle blockers block ACh from binding to nicotinic receptors – so this is like not being able to contract your muscles at all.
- Sugammadex:
- Mechanism: Selectively binds to steroid-based neuromuscular blockers (e.g., rocuronium, vecuronium), encapsulating them and reversing their effects.
- Uses: Rapid reversal of rocuronium and vecuronium.
- Best for: Patients needing fast neuromuscular recovery without cholinergic side effects.
- Special considerations: Not effective against succinylcholine, can cause bradycardia and anaphylaxis in rare cases.
- Population/Clinical Use: Ideal for reversing deep neuromuscular blockade in surgical patients, especially when rapid emergence is required.
- Neostigmine:
- Most commonly used in reversal.
- Acetylcholinesterase inhibitor —> increases acetylcholine —> competitive binding with NMB drugs —> reversal.
- Risk factors are DUMBELLS symptoms, hence why glycopyrolate is given along with neostigmine – think of it as prophylaxis for DUMBELLS symptoms.
📚 References
1️⃣ Miller RD. Miller’s Anesthesia. 9th ed. Philadelphia, PA: Elsevier; 2020.
2️⃣ Morgan GE, Mikhail MS, Murray MJ. Morgan & Mikhail’s Clinical Anesthesiology. 6th ed. New York, NY: McGraw Hill; 2018.
3️⃣ Steiner J. Anesthesia Made Easy: The Survival Guide to Make Your First Anesthesia Rotation a Success. 2nd ed. Independently Published; 2019.