Question

With this NMBA, patients will initially have muscle contractions before they become paralyzed.

A) Rocuronium
B) Succinylcholine
C) Vecuronium
D) Atracurium

Answer 1

Succinylcholine is the neuromuscular blocking agent that causes initial muscle contractions before inducing paralysis.

Step-by-step explanation:

The neuromuscular blocking agent (NMBA) that initially causes muscle contractions before paralysis is Succinylcholine (B). This reaction is known as fasciculation and it is characteristic of Succinylcholine's action. In contrast, drugs like Rocuronium, Vecuronium, and Atracurium do not typically cause muscle contractions prior to inducing paralysis.

Very briefly, NMBAs like d-tubocurarine work by competitively blocking the action of acetylcholine, preventing muscle contraction and causing paralysis.

Another substance, Botox, which is a form of botulinum toxin, prevents the release of acetylcholine from presynaptic terminals at neuromuscular junctions, also resulting in muscle paralysis, used for cosmetic purposes under the name Botox.

However, Succinylcholine has a unique initial action that can cause brief, mild muscle contractions before the muscle relaxation and paralysis occur.