Pharmacology of Neuromuscular Blocking Agents

Question 1

What is the MOA of depolarizing neuromuscular blockers?

Answer 1

Initially depolarize the cell, followed by persisted occupation of the receptor site that delays repolarization

Question 2

What is the MOA of Dantrolene?

Answer 2

Direct-acting skeletal muscle relaxant – Binds to ryanodine receptor 1 and decreases intracellular calcium

Question 3

What ADRs are associated with depolarizing neuromuscular blockers?

Answer 3

Muscle twitching, hyperkalemia, respiratory depression, increased ocular pressure, hypertension, tachycardia, arrhythmias, salivation

Question 4

What is the active metabolite of succinylcholine?

Answer 4

Succinylmonocholine

Question 5

What are the uses of Dantrolene?

Answer 5

Treatment of chronic muscle spasticity and malignant hyperthermia

Question 6

What is the major ADR associated with Dantrolene?

Answer 6

Hepatotoxicity

Question 7

What types of muscle fibers (slow/fast) are more susceptible to the effects of direct-acting skeletal muscle relaxants?

Answer 7

Fast-twitch muscle fibers

Question 8

What are the steroid derivative non-depolarizing neuromuscular blockers?

Answer 8

Vecuronium, Rocuronium

Question 9

When are non-depolarizing neuromuscular blockers contraindicated?

Answer 9

During overdose with depolarizing blockers - receptor sites will be blocked and OD effects will be prolonged

Question 10

This drug may be administered via IV during surgery to treat malignant hyperthermia.

Answer 10

Dantrolene

Question 11

What neuromuscular blocker is commonly used in emergency situations to facilitate intubation?

Answer 11

Succinylcholine

Question 12

What are the two types of neuromuscular blockers?

Answer 12

Depolarizing & Non-depolarizing

Question 13

What drug can be administered an an antidote for non-depolarizing neuromuscular blockers?

Answer 13

Sugammadex

Question 14

What are the isoquinolone derivatives?

Answer 14

Tubocurarine, Cisatracurium

Question 15

What are the contraindications for use of a depolarizing neuromuscular blocker?

Answer 15

History of malignant hyperthermia, narrow-angle glaucoma

Question 16

What is the MOA of Succinylcholine?

Answer 16

Depolarizing neuromuscular blocker

Question 17

True/False. Neuromuscular blockers penetrate the BBB.

Answer 17

False. They cannot penetrate the BBB, thus there is little CNS effect

Question 18

How can an overdose by a non-depolarizing neuromuscular blocker be treated?

Answer 18

Mechanical respiration, vasopressors, cholinesterase inhibitors

Question 19

What non-depolarizing neuromuscular blockers are most likely to increase histamine release?

Answer 19

Isoquinolone derivatives

Question 20

Cholinergic drugs and corticosteroids have what effect on neuromuscular blockers?

Answer 20

Reduce pharmacological effectiveness

Question 21

What is the MOA of direct-acting skeletal muscle relaxants?

Answer 21

Act directly on skeletal muscle fibers to decrease Ca2+ release

Question 22

Malignant hyperthermia is a serious ADR associated with what class of neuromuscular blockers?

Answer 22

Depolarizing blockers

Question 23

What is the MOA of non-depolarizing neuromuscular blockers?

Answer 23

Competitively bind to post-synaptic ACh cholinergic receptors

Question 24

What type of neuromuscular blocker produces flaccid paralysis?

Answer 24

Non-depolarizing blockers

Question 25

What are the primary uses of neuromuscular blockers?

Answer 25

Facilitate intubation, improve respiration with mechanical respirators

Question 26

Blocking of receptors by neuromuscular blockers beings (peripherally/centrally).

Answer 26

Peripherally. At low doses, rapidly contracting small muscles are first blocked and moves centrally. Recovery occurs in the reverse order, starting with the diaphragm and intercostal muscles.

Question 27

What is the MOA of sugammadex?

Answer 27

Encapsulates drug to prevent receptor binding