7 NMJ

Question 1

Which muscle type does NMJ drugs work on?

Answer 1

skeletal

Question 2

Why was NMJ drugs introduced in addition to diethyl ether?

Answer 2

diethyl ether was GOOD at inducing unconsciousness and analgesia but NOT very potent at muscle relaxation

Question 3

What was the first NMJ drug?

Answer 3

curare

Question 4

Neuromuscular blockers are specific to which type of receptor?

Answer 4

nicotinic ACh

Question 5

What are two classes of muscle relaxants?

Answer 5

depolarizing (sucs), non-depolarizing

Question 6

Succinylcholine

Answer 6

agonist for ACh
depolarizing, stimulates muscle (fasciculation)
very rapid, emergency use
metabolized by plasma cholinesterase

many side-effects

Question 7

Succinylcholine side effects

Answer 7

Bradycardia (esp. children).
• Muscle pains.
• Hyperkalaemia (burns, muscular disease, spinal injury)
• Allergy.
• ↑ intracranial & intraocular pressure.
• (Malignant hyperthermia.)
• (Prolonged in cholinesterase deficiency.)

Question 8

Are non-depolarizing NMJ drugs competitive or non-competitive inhibition?

Answer 8

competitive at the post-synaptic receptors

Question 9

two classes of non-depolarizing NMJ are?

Answer 9

Benzylisoquinolines

Aminosteroids

Question 10

Atracurium

Answer 10

Non organ-dependent elimination:
- Ester hydrolysis (enzymic).
- Hofmann degradation (non-enzymic).
• Causes histamine release.
• 10 stereo-isomers.

Question 11

What’s the advantage of Cisatracurium compared to Atracurium

Answer 11

1 of the isomers
Less histamine release.
• CVS stable

Question 12

Aminosteroids examples

Answer 12

Rocuronium
Vecuronium
Pancuronium

Question 13

aminosteroid advantages and composition

Answer 13

completely synthetic, two active sites joined by steroid group

No histamine release
CVS stable

Question 14

how do you monitor NMJ blockage?

Answer 14

Peripheral nerve stimulator

Question 15

If NMJ drug is overdosed, how would you reverse the effects?

Answer 15

Anti-Cholinesterase Drugs
• Inhibit Acetylcholinesterase.
• Increase ACh concentration.
• Displace drug from receptor.

Question 16

examples of anticholinesterase drugs

Answer 16

• Neostigmine.

* Edrophonium.

Question 17

In addition to Neostigmine, Edrophonium, what other drug must you give to reverse NMJ blockage?

Answer 17

atropine

Question 18

Why do you have to give atropine?

Answer 18

Anti-cholinergic drugs also increase ACh at the muscarinic receptors, causing undesired PNS activation.
atropine is an muscarinic antagonist, hence blocks the PNS activation when given with anti-cholinergic drug