Muscle relaxants

Question 1

Depolarizing

Answer 1

succinylcholine inihibits the post jct receptor and passively diffuses off the membrane,
while circulating the drug is metabolized by plasma esterases.
Associated with increased ICP/IOP, muscle fasciculations and post-op muscle aches, triggers MG,

Increases serum potassium especially in patients with burns, crush injury, spinal cord injury, muscular dystrophy, or disuse syndromes. Rapid and short acting

Question 2

Nondepolarizing

Answer 2

Many different kinds, all ending in “onium” or “urium”

Each has a different site of metabolism, onset, and duration making choice depend on specific patient and case

Question 3

Examples of non-depolarizing agents

Answer 3

Pancuronium- slow onset, long duration, tachycardia due to vagolytic effect

Cisatracurium- slow onset, intermediate duration, Hoffman (nonenzymatic) elimination so attractive choice in liver/renal disease

Rocuronium- fastest onset of nondepolarizers making it useful for rapid sequence induction, intermediate duration

Question 4

Reversal agents/anticholinergics

All the reversal agents are acetylcholinesterase inhibitors

Anticholinergics are given with reversal agents to block muscarinic effects of cholinergic stimulation, also excellent for treating bradycardia and excess secretions

Answer 4

All the reversal agents are acetylcholinesterase inhibitors
-more ACh available to overcome the neuromuscular blocker effect at the nicotinic receptir, also causing muscarinic stimulation

Neostigmine- shares duration of action with glycopyrrolate

Edrophonium- shares duation of action with atropine

Physostigmine- crosses BBB, useful for atropine overdose

Anticholinergics are given with reversal agents to block muscarinic effects of cholinergic stimulation, also excellent for treating bradycardia and excess secretions:
-Atropine- used in conjunction with edrophonium, crosses BBB causing drowsiness, may be bad at the end of surgery for reversal

premediaction in all children, since they tend to become bradycardic with intubation and produce copious drool

Glycopyrrolate- used in conjunction with neostigmine, does not cross the BBB