Lessons 7 & 8

Question 1

Where do neuromuscular blockers work?

Answer 1

At nicotinic cholinergic receptors at the postsynaptic neuromuscular junction

Question 2

Two types of neuromuscular blockers

Answer 2

Depolarizers and Non-depolarizers

Question 3

Depolarizing NMB

Answer 3

Only one on the market: succinylcholine

Binds alpha subunits of nicotinic cholinergic receptors

Question 4

Onset and duration of action for succinylcholine

Answer 4

30 second onset (look for fasiculations)

4-10 minute duration of action

Question 5

What breaks down succinylcholine?

Answer 5

Plasma cholinesterase aka pseudocholinesterase

Patients with an abnormal cholinesterase may experience a prolonged duration of action (i.e., cannot break down succinylcholine). This is also seen in patients with liver disease who cannot make enough pseudocholinesterase

Question 6

Life threatening complications d/t succinycholine

Answer 6

Severe hyperkalemia (especially in burn patients)

Cardiac arrest d/t bradycardia

Malignant hyperthermia

Question 7

Succinycholine is basically which molecule bound together

Answer 7

Succinycholine = 2 acetylcholine molecules bound together

Question 8

Non-depolarizing NMBs

Answer 8

They reversibly bind to, but do not activate, nicotonic cholinergic receptors

Question 9

How do you reverse vecuronium?

Answer 9

Neostigmine (anticholinesterase)

Question 10

What is the acetylcholine storm caused by reversal?

Answer 10

The “acetylcholine storm” is necessary to out-compete the NMB

…however…

this can also cause a cholinergic crisis (i.e., fatal bradycardia)

when anticholinesterase drugs are given, we always give a anticholinergic/antimuscarinic drugs as well (e.g., atropine)

Question 11

True/False

Vecuronium causes hypotension

Answer 11

False

Vecuronium does not release histamine at clinical doses

Question 12

Which non-depolarizing NMB accelerates HR

Answer 12

Pancuronium

P for pulse

Question 13

What is special about cisatracurium’s (aka Nimbex) elimination?

Answer 13

Metabolized by Hoffman Elimination

(drug is stable at room temp, but breaks down at body temp at a predictable rate)

Does not depend on renal or hepatic function

This is why Nimbex is used in patients w/ severe ARDS who are intubated and paralyzed

Question 14

Without prevention, post-op N/V will occur in…

Answer 14

in 33-50% of all surgical patients

Question 15

Drug treatment and prevention of PONV

Answer 15

Propofol

Dexamethasone

Zofran (5HT₃)

Metoclopramide

Question 16

Side effect of decadron in awake patients

Answer 16

Genital itching

Question 17

Side effect of promethazine (aka phenergan) in awake patients?

Answer 17

Extrapyramidal symptoms:

dystonia (continuous spasms and muscle contractions), akathisia (motor restlessness), parkinsonism (characteristic symptoms such as rigidity), bradykinesia (slowness of movement), tremor, and tardive dyskinesia (irregular, jerky movements)

Note: phenergan is not considered first line for PONV