Question

Austin has accidently taken an overdose of atracurium, a drug belonging to the class of nondepolarizing blockers. He slips into a state of respiratory paralysis and struggles to control his breathing.

What is the mechanism of action of atracurium that leads to respiratory paralysis?
(a) Atracurium binds to and blocks the nicotinic acetylcholine receptors at the neuromuscular junction, preventing the transmission of signals from the nerves to the muscles.
(b) Atracurium depolarizes the postsynaptic membrane at the neuromuscular junction, leading to prolonged muscle contraction.
(c) Atracurium inhibits the release of acetylcholine from the presynaptic nerve terminal.
(d) Atracurium activates the breakdown of acetylcholine.

Answer 1

Atracurium causes respiratory paralysis by binding to and blocking the nicotinic acetylcholine receptors at the neuromuscular junction, preventing muscle contraction.

Step-by-step explanation:

The mechanism of action of atracurium, which leads to respiratory paralysis when overdosed, is that atracurium binds to and blocks the nicotinic acetylcholine receptors at the neuromuscular junction. This blockage prevents the transmission of signals from the nerves to the muscles, leading to muscle relaxation and eventual paralysis. As a nondepolarizing blocker, atracurium competes with acetylcholine for the receptor sites, and without signal transmission, muscles, including the respiratory muscles, cannot contract, resulting in respiratory paralysis.