Neuromuscular blockade produced by rocuronium can be reversed by ?
**Core Concept**
Neuromuscular blockers like rocuronium act by competitively inhibiting the nicotinic acetylcholine receptors (nAChRs) at the neuromuscular junction (NMJ), preventing acetylcholine from binding and initiating muscle contraction. Rocuronium is a non-depolarizing neuromuscular blocker, which means it does not cause muscle fasciculations or depolarization.
**Why the Correct Answer is Right**
The reversal of neuromuscular blockade by rocuronium can be achieved by administering a cholinesterase inhibitor, such as neostigmine. Neostigmine increases the concentration of acetylcholine in the synaptic cleft by inhibiting the enzyme acetylcholinesterase, which breaks down acetylcholine. This allows acetylcholine to bind to the nAChRs, overcoming the competitive inhibition caused by rocuronium and restoring muscle contraction.
**Why Each Wrong Option is Incorrect**
* **Option A:** Atropine is an anticholinergic agent that would worsen the neuromuscular blockade by inhibiting acetylcholine release and increasing the concentration of acetylcholine in the synaptic cleft, which would not reverse the blockade.
* **Option B:** Succinylcholine is a depolarizing neuromuscular blocker that would further depress neuromuscular transmission, exacerbating the blockade.
* **Option D:** Fentanyl is an opioid analgesic that has no direct effect on neuromuscular transmission and would not reverse the blockade.
**Clinical Pearl / High-Yield Fact**
Remember the "NAR" mnemonic to recall the correct reversal agent for non-depolarizing neuromuscular blockers: **N**eostigmine, **A**cetylcholine, and **R**ecurrent neuromuscular transmission.
**Correct Answer:** C. Neostigmine