Certified Surgical Technologist (CST) Practice Exam

What is the only depolarizing muscle relaxant currently used in clinical practice?

1. Cisatracurium (Nimbex)

2. Vecuronium (Norcuron)

3. Rocuronium (Zemuron)

4. Succinylcholine (Anectine)

The correct answer is: Succinylcholine (Anectine)

Succinylcholine is known as the only depolarizing muscle relaxant currently used in clinical practice. Its mechanism of action differs from that of non-depolarizing muscle relaxants because it acts as a neuromuscular blocking agent by mimicking the action of acetylcholine at the neuromuscular junction, leading to an initial depolarization of the muscle membrane. This causes muscle fasciculations followed by muscle paralysis, which can be particularly useful during rapid sequence intubation or in situations where short-term paralysis is required. The other agents listed, such as cisatracurium, vecuronium, and rocuronium, are classified as non-depolarizing neuromuscular blockers. They work by competitively inhibiting acetylcholine from binding to its receptors at the neuromuscular junction, leading to muscle paralysis without the initial fasciculation seen with depolarizing agents. While these non-depolarizing agents are commonly used in various surgical procedures, they do not share the unique properties and effects of succinylcholine, which is specifically employed for its rapid onset and short duration of action.