Exam 10: NMJ Blockers Flashcards Preview

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Flashcards in Exam 10: NMJ Blockers Deck (26):
1

3 Non-depolarizing NMJ Blockers

Atracurium
Mivacurium
Rocuronium

2

1 Depolarizing NMJ Blocker

Succinylcholine

3

Where do NMJ Blockers have effects? Where do they not?

At NMJ...
NO CNS effects (don't cross the BBB)

4

Order of muscles to be paralyzed by NMJ blocker (recovery order?)

1. Small, rapidly moving muscles
2. Limb trunk muscles
3. Intercostals
4. Diaphragm
They recover in the reverse order

5

Dantrolene

Muscle relaxant (not complete)
Treatment for malignant hyperthermia
Also used to for long-term control of muscle spasms

6

3 botox uses

1. Blepharospasm (involuntary eyelid closing)
2. Strabismus (eye spasms)
3. Wrinkles

7

non-depolarizing NMJ blocker mechanism

Competitive inhibitors of ACh at the NMJ

8

reversal of non-depolarizing NMJ blockers

Cholinesterase inhibitors increase ACh at the NMJ, overcoming the competitive inhibition (Neostigmine)

9

2 side effects of non-depolarizing NMJ blockers

1. Prolonged apnea
2. Histamine release

10

Difference between -Curium and -curonium drugs

-curium: Benzylisoquinonlines (can cause histamine release, but don't have much vagal-blocking effect)
-curonium: Steroidal NMJ blockers (Can cause tachycardia due to vagal blockade, less prominent in Vecuronium or Rocuronium)

11

Sugammadex

Binds to and inactivates steroidal NMJ blockers (Rocuronium)
Approved in Europe, but not the USA

12

1 Short-acting non-depolarizing NMJ blocker

Mivacurium
Lasts 12-18 minutes

13

Mivacurium

Short acting non-depolarizing NMJ blocker
Metabolized quickly by plasma cholinesterase

14

2 Intermediate-acting non-depolarizing NMJ blockers

rocuronium
Atacurium
30-90 minutes

15

Rocuronium

Rapid onset
Used for rapid induction intubation
Lasts 30-90 minutes

16

Atacurium

Similar to rocuronium in effects, but is not metabolized by the liver
Useful in patients with liver or renal failure

17

1 Long duration non-depolarizing NMJ blocker

Pancuronium
2-3 hours

18

Pancuronium

Used to be used as the 2nd drug in the 3-drug lethal injection protocol

19

Succinylcholine

depolarizing NMJ blocker
fast onset, short duration
used for short procedures (intubation)
Causes fasciculations initially, before paralysis (twitching)
No antidote

20

Succinylcholine mechanism

alters electro-chemical driving force
causes excessive opening of nicotinic ACh receptors, decreasing the electrical driving force and therefore less response to motor neuron activity

21

Phase I succinylcholine

Fast onset (single dose)
Augmented by Neostigmine

22

Phase II succinylcholine

Slow onset (many doses)
Unknown exact mechanism
Neostigmine antagonizes Stage II block

23

Dantrolene mechanism

inhibits Ryanodine receptors

24

Dantrolene side effects

muscle weakness
liver toxicity

25

Botox mechanism

Prevents ACh release at the NMJ

26

Botox side effect

Can cause up-regulation of nicotinic ACh receptors, resulting in increased wrinkling and ptosis