Rocuronium 1.2 mg/kg achieves conditions comparable to succinylcholine for rapid sequence intubation. When sugammadex is given at the end of surgery, what is the mechanism by which rocuronium block is reversed?

• A Competitive displacement of rocuronium from nicotinic receptors by sugammadex
• B Inhibition of plasma pseudocholinesterase that normally breaks down rocuronium
• C Allosteric modulation of acetylcholine receptor to increase its sensitivity to acetylcholine
• D Encapsulation of rocuronium molecules in a hydrophilic cavity, reducing free plasma concentration ✓

Explanation

Sugammadex is a modified gamma-cyclodextrin that forms a tight 1:1 inclusion complex (host-guest encapsulation) with steroidal neuromuscular blocking agents, particularly rocuronium. By trapping free rocuronium in plasma, the concentration gradient reverses and rocuronium dissociates from nicotinic receptors at the neuromuscular junction, restoring normal transmission. The mechanism is entirely pharmacokinetic (sequestration), not pharmacodynamic competition. Neostigmine works pharmacodynamically by inhibiting acetylcholinesterase; sugammadex's mechanism is fundamentally different.

Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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