Muscle Relaxants

Question 1

What is the primary use of Neuromuscular Blockers?

Answer 1

adjunct to general anesthesia to relax muscles without cardiorespiratory depression
Lack CNS activity

Question 2

Spasmolytic indications

Answer 2

Chronic Back Pain
Fibromyalgia
Muscle Spasms
“Central Acting” muscle relaxants

Question 3

2 categories of Neuromuscular blockers

Answer 3

1. Nondepolarizing agents

2. Depolarizing agents

Question 4

Nondepolarizing agent mechanism

Answer 4

Competitive antagonist at the nAChR that blocks depolarization

Question 5

Depolarizing agent mechanism

Answer 5

causes excess depolarization with no repolarization. Leads to flaccid paralysis

Question 6

What duration of action is most preferred for the neuromuscular blocking agents?

Answer 6

Intermediate- 20-60m

Question 7

Adverse effects of Neuromuscular blockers

Answer 7

Effects lasting too long
Hypotension with Tachy
Histamine release (bronchoconstriction, salivary secretion)

Question 8

What is used to reverse NMJ blockage

Answer 8

AChE inhibitors

Anticholingeric co-administered to minimize mAChR overactivation

Question 9

What is the most clinically relevant depolarizing agent?

Answer 9

Succinylcholine

Question 10

Phase 1 Block of Succinylcholine

Answer 10

Depolarizes membrane and prevents repolarization

Question 11

Phase 2 Block of Succinylcholine

Answer 11

membrane repolarizes but is desensitized and doesn’t depolarize, similar to nondepolarizing block. Reversed by AChE inhibitor

Question 12

4 uses for NMBDs

Answer 12

1. Surgical relaxation
2. Tracheal Intubation
3. Control of Ventilation
4. Treatment of Convulsions

Question 13

Drugs used for rapid intubation

Answer 13

Succinylcholine
Rocuronium
Vecuronium

Question 14

Drugs used as adjuncts to anesthesia

Answer 14

Pancuronium
Atracurium
Cisatracurium

Question 15

Spasmolytic Agents

Answer 15

relax spastic muscle seen in cerebral palsy, MS, and stroke. Can be centrally acting or non-centrally acting

Question 16

Centrally acting spasmolytic agents

Answer 16

Baclofen (GABAb agonist)
Carisoprodol (unknown MOA)
Cyclobenzaprine aka Flexeril (unknown MOA)
Diazepam (Benzo)

Question 17

Non-centrally acting spasmolytic agents

Answer 17

Dantrolene- Ryanodine receptor antagonist that inhibits Ca release from SR

Botox- inhibits ACh release

Question 18

Agents for MS

Answer 18

Glucocorticoids (in acute attack)
Interferons- interferes with T-cell adhesion
Glatiramer Acetate- activates Tregs to save MBP
Mitoxantrone- DNA intercalating agent

Question 19

Adverse effects of non depolarizing agents

Answer 19

Histamine release–> wheals, bronchospasm, hypotension, bronchial/salivary secretion

Question 20

Drug-Drug interactions with Non-depolarizing NMBD

Answer 20

Aminoglycosides and some other classes of ABX

Question 21

How do burn patients or those with UMN diseases react to non depolarizing NMBD?

Answer 21

They are resistant

Question 22

How can you recognize a non depolarizing NMBD

Answer 22

-cur- in the name (Atracurium, Cisatracurium, Doxacurium, etc)

Question 23

What are the steroid derivative muscle relaxants and why are they good?

Answer 23

Less Histamine release.
Vecuronium, Rocuronium, Pancuronium, Pipecuronium,

With steroids, you are Very Red & your Penis is Poppin’

Question 24

What drug can be given as an alternative to Succinylcholine?

Answer 24

Rocuronium

Question 25

Black box warning of Succinylcholine

Answer 25

Rhabdomyolysis with Hyperkalemia

Question 26

How do you treat malignant hyperthermia?

Answer 26

Dantrolene

Question 27

Baclofen

Answer 27

GABAb agonist that hyper polarizes and inhibits neurotransmitter release

Question 28

Tizanidine

Answer 28

a2-agonist that decreases input to alpha motor neurons

Question 29

Dantrolene

Answer 29

RyR inhibitor that stops efflux of Ca from SR in muscle

Cardiac and SM not affected