MSK: Skeletal Muscle Relaxants

Question 1

What is the root word of all the non-depolarizing neuromuscular blockers?

Answer 1

-cur-

Question 2

What is the only depolarizing neuromuscular blocker?

Answer 2

Succinylcholine

Question 3

What are the centrally acting spasmolytics? (5)

Answer 3

Baclofen
Carisprodol
Cyclobenzaprine
Diazepam
Tizanidine

Question 4

What are the non-centrally activating spasmolytics? (2)

Answer 4

Dantrolene

Botulism toxin

Question 5

What are the immunologic drugs for MS? (according to Kruse)

Answer 5

Glucocorticoids
Glatiramer Acetate
Interferons (beta)
Mitoxantrone

Question 6

How do the non-depolarizing (-curarines) work to cause muscle paralysis?

Answer 6

Prevents acess to ACh as a pure antagonist effect

Question 7

What is the effect of succinylcholine on muscles?

Answer 7

Excess depolarization causes flaccid paralysis

Question 8

Which neuromuscular blocker is fastest onset, and has shortest duration?

Answer 8

Succinylcholine

-used when inducing intubation due to rapid on and off effects

Question 9

What drugs are the intermediate acting neuromuscular blockers? (4)

Answer 9

Atracurium
Cisatracurium
Rocuronium
Vecuronium

Great for adjuncts to general anesthesia to do intermediate duration

Question 10

Which class of neuromuscular blockers cause the least amount of histamine to be released with them?

Answer 10

Steroid derivatives

-Pancuronium, Pipercuronium, Rocuronium, and Vecuronium

Question 11

How do you reverse the neuromuscular blockade?

Answer 11

Cholinesterase inhibitor (-stigmine) + Anticholinergic (atropine, glycopyrrolate) to reduce effects of Ach at mAChRs

Question 12

Why do some people have prolonged effects from succinylcholine?

Answer 12

They have a polymorphism in pseudocholinesterase

• cannot break down succinylcholine as fast
• -just wait it out, and eventually they will have less paralysis

Question 13

Describe the phases of succinylcholine

Answer 13

Phase 1=depolarizing
-this phase produces the flaccid paralysis

Phase 2=desensitizing
-nerves become less sensitized, and membrane becomes repolarized

Question 14

Which phase (1 or 2) can be reversed with cholinesterase inhibitors?

Answer 14

Phase 2

-phase 1 is not affected

Question 15

Ambenonium, Echothiophate, and tacrine MOA?

Answer 15

AChE inhibitors

Question 16

Donepezil, galantamine, and Rivastigmine MOA? Clinical Use?

Answer 16

AChE inhibitors used in Alzheimer’s

Question 17

Physostigmine, Pyridostigmine, neostigmine, and edrophonium MOA? clinical use?

Answer 17

AChE inhibitors;

• can be used to reverse pharmacologic paralysis
• Mysthenia Gravis
• Antidote to anticholinergic poisoning

Question 18

Baclofen MOA? Adverse effects?

Answer 18

GABAb agonist resulting in inhibition of excitatory NT release

Adverse: drowsiness and increased seizure activity in epileptics

Question 19

Carisoprodol Clinical use?

Answer 19

Spasmolytic and has anxiolytic effect

Question 20

Adverse effects of carisoprodol?

Answer 20

Addictive potential

Question 21

Clinical use of Cyclobenzaprine?

Answer 21

Spasmolytic

Question 22

Adverse effects of cyclobenzaprine?

Answer 22

Drowsiness, dizziness, xerostomia

Question 23

MOA of diazepam? Adverse effects?

Answer 23

MOA: GABAa receptor agonist; decreases excitatory NTs

Adverse: CNS depression

Question 24

MOA of tizanidine? Adverse effects?

Answer 24

MOA: a2 agonist used as antispasmotic

Adverse: CNS depression, hypotension, dry mouth

Question 25

MOA of glatiramer acetate for MS?

Answer 25

mixture of random polymers of four amino acids thought to induce and activate T-cell supressors specific for a myelin antigen

Question 26

MOA of interferons for MS?

Answer 26

Act on blood brain barrier by interfering with T-cell adhesion to endothelium, or by inhibiting T-cell expression of myelin basic protein

Question 27

MOA of mitoxantrone for MS?

Answer 27

Intercalates into DNA resulting in cross-links and strand breaks -decreases immune response by causing apoptosis in lymphocytes

Question 28

Clinical use of diazepam?

Answer 28

Sedation, muscle relaxant, anxiolytic, and anti-convulsant (status epilepticus)

Question 29

MOA of Dantrolene

Answer 29

Binds to RYR receptor to block release of calcium into muscle cell -less contraction

Question 30

Clinical use of dantrolene

Answer 30

Spasticity and treatment for malignant hyperthermia**

Question 31

MOA of Botulism toxin?

Answer 31

cleaves SNARE proteins, prevents release of ACh into synaptic cleft -reduces muscle spasms