Shortest acting skeletal muscle relaxant is –
**Core Concept**
The question tests the knowledge of skeletal muscle relaxants, specifically their duration of action. In clinical practice, the choice of muscle relaxant depends on the desired duration of relaxation and the underlying condition being treated.
**Why the Correct Answer is Right**
The shortest-acting skeletal muscle relaxant is succinylcholine. It acts by depolarizing the muscle cell membrane, leading to muscle relaxation. Succinylcholine is a cholinergic agonist that mimics the action of acetylcholine at the nicotinic receptors in the neuromuscular junction. It is rapidly broken down by the enzyme plasma cholinesterase, resulting in a short duration of action. This makes it ideal for procedures requiring brief muscle relaxation, such as endotracheal intubation.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify a well-known muscle relaxant with a short duration of action.
**Option B:** This option is incorrect because it is not a muscle relaxant commonly used in clinical practice.
**Option C:** This option is incorrect because it is not the shortest-acting muscle relaxant available.
**Clinical Pearl / High-Yield Fact**
Succinylcholine should be used with caution in patients with underlying muscle disease, such as Duchenne muscular dystrophy, as it can cause severe hyperkalemia.
**Correct Answer: D. Succinylcholine. Succinylcholine**