Unit 3- Neuromuscular Blockers

Question 1

Competitive Nondepolarizing Agents

Answer 1

Block nicotinic receptors to prevent Ach binding

Question 2

Depolarizing Agents

Answer 2

Cause initial membrane depolarization before paralysis

Question 3

Nicotinic Receptors

Answer 3

Require ionic binding of 2 Ach, opens channel to allow Na+ in the cell

Question 4

Tetrodotoxin

Answer 4

Decrease permeability of Na+ to cause muscle paralysis

Question 5

Local Anesthetics

Answer 5

Inactivate Na/K channels to prevent action potential

Question 6

Hemicholinium

Answer 6

Interferes with reuptake

Question 7

Botulinum Toxin

Answer 7

Interferes with Ach vesicles with the plasma membrane to prevent Ach release

Question 8

Cholinesterase Inhibitors

Answer 8

Decrease AchE activity, Ach accumulates at receptors

Question 9

Magnesium Ion

Answer 9

Competes with Ca++ transport into the nerve, interfering with Ach release and decreasing postsynaptic Ach sensitivity

Question 10

Aminoglycoside Antibiotics

Answer 10

Inhibit Ach release by lowering Ca++ availability at axon terminal, decrease postsynaptic Ach sensitivity

Question 11

Depolarizing Agents Elimination

Answer 11

Hydrolysis by cholinesterase

Question 12

Competitive Nondepolarizing Agent Elimination

Answer 12

Hepatic metabolism or hoffmann elimination

Question 13

Hofmann Elimination

Answer 13

Elimination without enzymes affected by temp or pH

Question 14

Benzylisoquinoliniums

Answer 14

Nondepolarizing competitive agents, atracurium, cisatracurium, mivacurium, doxocurium

Question 15

Aminosteroid Agents

Answer 15

Nondepolarizing competitive agents, vecuronium, rocuronium, pancuronium

Question 16

Asymetric Chlorofumarates

Answer 16

Nondepolarizing competitive agent, gantacurium

Question 17

Atracurium

Answer 17

Muscle relaxation during surgery, intubation, safe in renal or hepatic insufficiency, urethral obstruction removal, minimal cardiovascular effect, pH and temp affect elimination

Question 18

Cisatracurium

Answer 18

Similar to atracurium

Question 19

Pancuronium

Answer 19

Muscle relaxation during surgery, intubation, inconsistent cardiac effects

Question 20

Vecuronium

Answer 20

Muscle relaxation during surgery, hepatic metabolism, minimal cardiac effects

Question 21

Rocuronium

Answer 21

Rapid onset, no cardiovascular effects

Question 22

Gantacurium

Answer 22

Ultra short duration, degraded in plasma

Question 23

Succinylcholine

Answer 23

Depolarizing agent, rapid onset with short duration, prolonged depolarization of end plate, phase I and II block

Question 24

Phase I Succinylcholine Block

Answer 24

Open cation channel and depolarize , increased cation permeability, muscle fasciculation

Question 25

Phase II Succinylcholine Block

Answer 25

Cation channel closes and repolarizes, junction resistant to depolarization, flaccid paralysis

Question 26

Neuromuscular Blocker Paralysis Progression

Answer 26

Face, limbs, larynx, abdominals, intercostals, diaphragm

Question 27

Dosing of Neuromuscular Blockers

Answer 27

Sufficient to paralyze limbs but not diaphragm

Question 28

Margin of Safety

Answer 28

Large majority of receptors must be blocked to prevent muscle twitch

Question 29

Reversal of Blockers

Answer 29

Initiate ventilation, withdraw administration, avoid synergistic drugs, use AchE inhibitors and cyclodextrin to reverse

Question 30

AchE Inhibitors

Answer 30

Inhibit AchE to reverse nondepolarizing drugs

Question 31

Succinylcholine

Answer 31

Reverses depolarizing agents

Question 32

Edrophonium

Answer 32

AchE inhibitor used to reverse neuromuscular blockage