What type of muscle response does Succinylcholine induce during administration?

Succinylcholine is a depolarizing neuromuscular blocker that initially activates nicotinic receptors at the neuromuscular junction. This initial activation leads to muscle contractions, which can manifest as muscle fasciculations. These fasciculations are brief, involuntary twitching of the muscle fibers, and occur before the subsequent phase of paralysis as the drug prevents further contraction by maintaining a prolonged depolarization of the receptor.

The mechanism of action involves binding to the acetylcholine receptors, mimicking the action of acetylcholine, but unlike acetylcholine, succinylcholine is not broken down quickly and continues to activate the receptors. After the initial wave of muscle fasciculations, the persistent depolarization causes a neuromuscular block, leading to muscle relaxation, but the defining characteristic upon initial administration is the presence of these fasciculations.

Thus, recognizing that muscle fasciculations are characteristic of succinylcholine administration helps clarify the response it induces before leading into its paralyzing effects.