All of the following statement about neuromuscular blockage produced by succinylcholine are true except
Depolarizing neuromuscular blocker The only drug still in clinical use belonging to this group is succinylchloline. Mode of action The effects of succinylcholine (SCh)at the neuromuscular junction are depolarizing postsynaptic and extrajunctional receptors, normally, this desensitization process does not occur with acetylcholine because of its rapid breakdown. However, succinylcholine remains at the endplate for much longer, so desensitization develops after a brief period of activation. Neuromuscular blockade because a depolarized neuro muscular blockade cannot respond to subsequent acetylcholine release. SCh is endowed with two unique and critically impoant characteristics - 1.produces intense paralysis rapidly(fastest onset) 2.effect wanes before preoxygenated person beomes hypoxic (shoest duration). Within 1 minute after succinylcholine injection and before paralysis are manifested, disorganized movements or fasciculation is seen. Characteristics of blockade 1. Simple twitch height reduces 2. No fade on train of four stimulation 3. No fade on tetanic stimulation 4. Potentiated by inhibitors of acetylcholinesterase 5. High dose > 4-6 mg/kg body weight in multiple dosing or single dose changes the characteristic of block from depolarizing to nondepolarizing. This is termed nondepolarizing dual or phase II block. When succinyl choline enters phase II block it stas showing character of nondepolarizing NMB.
No fade on Train of Four stimulation
Fade on tetanic stimulation
No post tetanic fecilitation
Train of four ratio 1
Neuromuscular Blocker