NMB Reversals

Question 1

Acetylcholine is broken down by what? what are the byproducts?

Answer 1

acetylcholinesterase breaks it down into choline and acetate

Question 2

Do AchE inhibitors eliminate need to eliminate NMBs from the body?

Answer 2

No, just increase Ach concentration at NMJ, NMB still have to be eliminated from the body

Question 3

How does AchE work?

Answer 3

1. enzyme inhibition
2. pre-synpatic effects

Question 4

describe the three bonds that can occur with enzyme inhibition of AchE which are competitive antagonism vs non-competative?

Answer 4

electrostatic attachment-competitive
formation of carabmol esters-competitive
phosphorylation non-competitive

Question 5

which AchE inhibitors use each form of enzyme inhibition?

Answer 5

edrophonium - electrostatic attachment

neostigmine, pyridostigmine, physostigmine - carbamol esters

organophosphates and echothiopate - phosphyrlation

Question 6

What is the mech of action for AchE pre-synaptic effects

Answer 6

1. AchE stimulate presynpatic R (like sux) causing increased Ach release

or

2. AchE increases Ach in the NMJ which then binds the presynaptic R itself.

Question 7

How do anti-AchE affect psuedocholinesterase?

Answer 7

neostigmine and pyridostigmine inhibit it. Can lead to prolonged block from sux if given after neostigmine or pyridostigmine.

Edrophonium has no effect.

Question 8

Do you need dose adjustments for AchE inhibitors in renal failure?

Answer 8

no, renal failure prolongs both NMBs and Anti-AchEs so no need to change doses

Question 9

in which populations does neostigmine work the most quickly?

Answer 9

works faster in infants and children than adults

Question 10

What happens if you give a huge dose of AchE inhibitor?

Answer 10

AchE inhibitors have a ceiling effect, so all yo get beyond max dose is more side effects

Question 11

Do quaternary amines or tertiary amines cross the BBB?

Answer 11

tertiary amines. Quaternary amines do not cross BBB

Question 12

which AchE inhibitors are quaternary amines?

Answer 12

edrophonium
neostigmine
pyridostgmine

Question 13

what AchE inhibitors ar tertiary amines?

Answer 13

physiostigmine

Question 14

what TOF ratio increases risk of PPC?

Answer 14

<0.9

Question 15

when can AchE inhibitors caues muscle weakness

Answer 15

this can occur paradoxically if AchE inhibitor is given after full recovery from NMB is acheived

Question 16

which antimuscarnics pair best with the following AchE inhibitors?

Edrophonium
neostigmine
pryidostgmine

Answer 16

atropine
glyocpyrrolate
glyocpyrrolate
respectively

Question 17

Edrophonium dose, onset, doa, and metabolim/elimination

Answer 17

dose: 0.5-1.0mg/kg
onset: 1-2min
doa: 30-60min
metabolism/elimination
renal 75%
liver 25%

Question 18

neostigminedose, onset, doa, and metabolim/elimination

Answer 18

0.02-0.07mg/kg
onset: 5-15min
doa: 45-90min
M/E: 50/50 renal/liver

Question 19

pyridostigmine dose, onset, doa, and metabolim/elimination

Answer 19

dose: 0.1-0.3mg/kg
onset: 10-20min
doa: 60-120min
M/E: renal 75% liver 25%

Question 20

can neostigmine be used intrathecally? if so what is the dose and associated side effects?

Answer 20

yes
50-100mcg
produces analgesia
SE: n/v, pruritis, prolongation of sensory and motor block

Question 21

which AchE inhibitor can be used for post-op shivering? what is the dose? how does it compare to other options to stop shivering?

Answer 21

physostigmine 40mcg/kg

efficacy matches meperidine and clonidine for anishivering effects

Question 22

Classic AchE Inhibitor side effects?

Answer 22

Dumbbells

diarrhea
urination
miosis
bradycardia
bronchoconstriction
emesis
lacrimation
laxation (defecation)
salivation

Question 23

which antimuscarnics increase HR the most?

Answer 23

atropine > glyco > scopolamine

Question 24

which antimuscarnics cause sedation? which causes the most?

Answer 24

scopolamine > atropine

Question 25

which antimuscarnics cause the most dry mouth?

Answer 25

scopolamine > glyco > atropine

Question 26

which antimuscarnics cause the most mydriasis and cycloplegia?

Answer 26

scopolamine > atropine cycloplegia: temporary paralyzed ciliary m. causing blurry vision

Question 27

how do anti muscarnics affect gastric H+ secretion?

Answer 27

they all decrease it by the same magnitude (equally)

Question 28

which antimuscarinics cross the BBB? which do not?

Answer 28

atropine and scopolamine, tertiary amines cross BBB glyco, quaternary amine does not cross the BBB

Question 29

do tertiaty or quarternary amines cross the BBB

Answer 29

tertiary amines cross the BBB

Question 30

what can a small dose of atropine cause? what is the mech of action? <0.5mg

Answer 30

paradoxical bradycardia inhibits presynaptic M1 receptors on vagal nerve endings, blocking the negative feedback loop > continued Ach release and bradycardia

Question 31

antimuscarnic considerations in patients who have undergone heart transplant

Answer 31

anti-muscarinics will not effect heart rate, still give them with AchE inhibitors when reversing NMB though to prevent the other side effects.

Question 32

sugammadex med class

Answer 32

gamma-cyclodextrin

Question 33

sugammadex SE

Answer 33

anaphylaxis 0.3% of patients bradycardia decrease effectiveness of hormonal birth control for up to 7 days

Question 34

sugammadex can be used to reverse which NMBs?

Answer 34

Roc Vec and Pacuronium. Works the best for Roc though

Question 35

What if you need to re-paralyze after using suggamadex?

Answer 35

Can always use steroid not from amino steroid class. Sux, cisatracurium, etc. if dose was < or equal to 4mg/kg 5min-4hrs after Roc at 1.2mg/kg if >4hrs Roc at 0.6mg/kg If 16mg/kg given within 24hrs must use NMB outside of aminosteroid class

Question 36

what molar concentration between Roc and sugammadex do you need? How does this affect dosing?

Answer 36

Need 1:1 molar concentration between Roc and suggamadex. this is why sugammadex dose is based on block density

Question 37

how are suggamadex-roc complex metabolised/eliminated?

Answer 37

excreted unchanged by the kidneys

Question 38

is the affinity of suggamadex for roc reversible?

Answer 38

technically yes, affinity is very strong but it is reversible.

Question 39

Sugammadex dosing

Answer 39

TOF 2/4 2mg/kg TOF 0/4 with 2 PTC or more 4mg/kg after 1.2mg Roc, wait 3 min then 16mg/kg