Anaesthetic agents

Question 1

Suxamethonium

• Class
• MoA
• Indications
• Contraindications
• Side effects

Answer 1

Class:
Depolarising neuromuscular blocking agent

MoA:
Binds to nicotinic acetylcholine receptors resulting in persistent depolarization of the motor end plate

Indications:
Muscle relaxant of choice for rapid sequence induction

Contraindications:
Penetrating eye injuries or acute narrow glaucoma

Side effects:
Malignant hyperthermia, hyperkalemia, fasiculations

Question 2

Propofol

• MoA
• Adavantages
• Disadvantages

Answer 2

MoA:
GABA receptor agonist

Advantages:
Anti-emetic effects, rapid onset, induction and maintenance

Disadvantages:
Pain on injection, myocardial depression (hypotension)

Question 3

Sodium thiopentone

• MoA
• Advantages
• Disadvantages

Answer 3

MoA:
Short-acting barbituate (prolonged opening of chloride channels on GABA neurons)

Advantages:
Very fast acting

Disadvantages:
Myocardial depression, little analgesia, unsuitable for maintenance, laryngospasm

Question 4

Ketamine

• MoA
• Advantages
• Disadvantages

Answer 4

MoA:
NMDA receptor antagonist

Advantages:
Doesn’t lower blood pressure as much, strong analgesic, induction and maintenance

Disadvantages:
Nightmares, disorientation

Question 5

Etomidate

• MoA
• Advantages
• Disadvantages

Answer 5

MoA:
Potentiates GABA

Advantages:
Little haemodynamic influence

Disadvantages:
No analgesia, unsuitable for maintenance, adrenal suppression, post-operative vomiting, myoclonus

Question 6

Nitrous oxide

• MoA
• Advantages
• Disadvantages

Answer 6

MoA:
Unknown

Advantages:
Can maintain analgesia

Disadvantages:
Used for maintenance only, contraindicated in pneumothorax

Question 7

Volatile liquid anaesthetics

• MoA
• Advantages
• Disadvantages

Answer 7

MoA:
Unknown

Advantages:
Used for induction and maintenance

Disadvantages:
Myocardial depression, malignant hyperthermia