Which drug is a rapidly acting depolarizing neuromuscular blocker used for intubation?

• A. Propofol
• B. Succinylcholine
• C. Dexmedetomidine
• D. Fentanyl

Answer: (B)

For rapid intubation you need a drug that quickly stops movement of the airway muscles. Succinylcholine is a depolarizing neuromuscular blocker with the fastest onset, typically 30 to 60 seconds, and a short duration of effect about 5 to 10 minutes. It works by binding to nicotinic acetylcholine receptors at the neuromuscular junction, causing an initial brief twitch (fasciculations) followed by sustained depolarization that prevents further stimulation, resulting in rapid, short-lived paralysis. This rapid onset and brief duration make intubation faster and safer in many emergency or emergency-like settings.

Other agents here are not neuromuscular blockers. Propofol is an induction anesthetic that helps you lose consciousness but does not paralyze muscles. Dexmedetomidine is a sedative, and fentanyl is an analgesic; neither provides the muscle paralysis needed to facilitate intubation.