Neuromuscular Blocking Agents

Question 1

Succinylcholine advantages

Answer 1

Most rapid onset
Shortest duration
RSI

Question 2

Succinylcholine disadvantages

Answer 2

Contraindicated in burn and stroke
Can cause lethal hyperkalemia due to extrajunctional Ach receptors
MH!!!

Question 3

Succinylcholine dose

Answer 3

1-2mg/kg
Typically we give 100 in the OR
This might not be enough for larger patients

Question 4

Vecuronium dose

Answer 4

0.1 mg/kg

We typically give 10 mg

Question 5

Rocuronium advantages

Answer 5

Best alternative to sux for RSI

Question 6

Rocuronium dose

Answer 6

0. 6 mg/kg

1. 2 mg/kg for RSI

Question 7

Cisatracurium advantages

Answer 7

Used is renal and liver disease patients

Does not rely on liver or kidney for metabolism or excretion

Question 8

Cis dose

Answer 8

0.2 mg/kg

Question 9

Cis onset and duration

Answer 9

2 min

1 hour

Question 10

Neostogmine MOA

Answer 10

Anticholinesterase that increases the amount of acetylcholine throughout the body
This reverses the blockade

Question 11

Neostigmine dose

Answer 11

0.07 mg/kg up to 5 mg

Can be decreased depending on TOF

Question 12

Glycopyrrolate use

Answer 12

Offsets the bradycardia caused by acetylcholine

Question 13

Glycopyrrolate dose

Answer 13

0.2 for every mg of neostigmine given

For quick calculation you can just draw up the same volume of glyco as neo

Question 14

Nondepolarizing NMBDs MOA

Answer 14

Compete with ACh for alpha subunit of the nicotinic receptor

Question 15

Describe the characteristics of sux phase I and phase II blocks

Answer 15

I: depolarized, TOF ratio is 1. No further contractions
II: receptor available sux defused away, but still not a normal response to stimulation, TOF ratio has a fade

Question 16

Calcium dependent presynaptic release of ACh

Effects of calcium and magnesium levels

Answer 16

High magnesium inhibits (OB)

High calcium increase ACh release, so the patient will need more muscle relaxant

Question 17

What is the structure of the postjunctional ACh receptor?
Where is acetylcholinesterase located?
How does the structure of extra junction all ACh receptor differ?

Answer 17

5protein units
2 alpha units where NMBs bind
Postjunctional membrane, near the receptor
Gamma subunit, stays open longer

Question 18

Name the enzyme that breaks down sux

Answer 18

Butyrylcholinesterase AKA pseudocholinesterase
Remi is broken down by nonspecific cholinesterase
esmolol is broken down by RBC cholinesterase

Question 19

Is sux contraindicated in CP?

Answer 19

No

Question 20

Renal failure and its effects of panc, vec/roc, cis, and mica/sux

Answer 20

Pancuronium starts with a P, excreted in the pee, so longest
Vec and roc are intermediate
Cisatracurium is spontaneously degraded by Hoffman elimination

Question 21

Is sux contraindicated in liver disease?

Answer 21

No, but you may need a higher dose because of extra water space and higher Vd
The block may last longer because liver makes plasma cholinesterase

Question 22

Which part of the NMJ is affected in Eaton lambert?

Which NMBs are they more sensitive to? Why?

Answer 22

Presynaptic Ca channel

Both depoland non depol because there are more ACh receptors and less synaptic ACh to compete with

Question 23

How does myasthenia gravis affect the pt response to NMB?

Answer 23

Less postjunctional ACh receptors

Therefore resistance to Sux and sensitive to ND

Question 24

How does myotonic dystrophy affect contraction?

Answer 24

Dystrophin is messed up, so contraction happens normally, but relaxation takes WAY longer
For this reason, you should avoid SCh
Response to ND is normal, but it does not relieve contracture

Question 25

Which ion channel causes potassium fluctuations in periodic paralysis? How do you treat it?

Answer 25

Na | Acetazolamide

Question 26

Which form of periodic paralysis should you avoid SCh?

Answer 26

Hyperkalemic (duh)

Question 27

What does the dibucaine number tell you? | If someone has a dinucaine number <80, which drugs could be prolonged?

Answer 27

Quality of pseudocholinesterase SCh, mivacurium, and ester LAs NOT remi or esmolol

Question 28

Cyclophosphamide and echothiophate inhibit and inactivate which enzyme? How would you treat prolonged recovery due to these drugs?

Answer 28

Pseudocholinesterase | ABC, FFP if necessary

Question 29

Which NMB is vagolytic? | Which NMB causes bradycardia?

Answer 29

Pancuronium | SCh (cholinergic at muscarinic receptor)

Question 30

Mac dose rationale of neostigmine

Answer 30

Ceiling: excess ACh can cause a depolarizing block like SCh

Question 31

After reversal and extubation, a pt has laryngospasm and is give SCh for reintubation. You notice that they remained paralyzed for longer than usual with SCh. Why?

Answer 31

Neostigmine inhibits pseudocholinesterase

Question 32

Both botulism and tetanus block presynaptic release of a ACh. So why then are tetanic pts contracted?

Answer 32

Tetanus toxin block inhibitory neurons

Question 33

Nerve gases and organophosphate do what?

Answer 33

Block acetylcholinesterase

Question 34

TOF >0.9 could still mean poor swallow and risk of aspiration

Answer 34

Remember that

Question 35

Which drugs does butyrylcholinesterase act on?

Answer 35

SCh Ester anesthetics Mivacurium

Question 36

What is the MOA of donepezil?

Answer 36

Acetylcholinesterase inhibitor Reversible! It is a central inhibitor it crosses the blood brain barrier

Question 37

How does Aricept interact with SCh? Nondepolarizers?

Answer 37

Donepezil can also cross over and Inhibit pseudocholinesterase which will prolong the action of succinylcholine Because donepezil inhibits acetylcholinesterase there will be increased acetylcholine in the cleft which could possibly require higher doses to maintain blockade with a non-depolarizer Manufacturers recommend withholding Aricept at least two weeks prior to scheduled surgeries

Question 38

Are skeletal muscles nicotinic or muscarinic

Answer 38

Nicotinic

Question 39

Will hypocalcemia attenuate or prolong presynaptic release of acetylcholine?

Answer 39

Attenuate, the presynaptic neuron needs to influx calcium in order to release acetylcholine Under these conditions you will need less NMB

Question 40

What affect does lithium have on NMB?

Answer 40

Lithium potentiates both nondepolarizer’s and depolarizers It also decreases Mac