Flashcards in Anaesthesia Deck (17):
What is the mode of action of Curare?
Nicotinic acetylcholine receptor antagonist (nAChR)
What is the mode of action of Atropine?
Muscarinic acetylcholine receptor antagonist (mAChR)
What is the mode of action of Phenobarbital? What is it used for?
GABA receptor agonist, increasing the flux of Cl- into a neurone which decreases its excitability. Used to treat epilepsy.
What is MAC (Minimum Alveolar Concentration)?
The concentration of a vapour in the lungs required to prevent movement in 50% of patients
What are the two groups of general anaesthetics?
Intravenous general anaesthetics
Volatile general anaesthetics
Give three examples of general anaesthetics which are volatile
What is the mechanism of action of Isoflurane?
Neuronal ion channel modulator, it decreases the conductance of a neurone by decreasing the opening time and increasing the closing time
Give three examples of general anaesthetics which are intravenously administered
Describe the mechanism of action of Propofol?
GABA modulator, slowing down its closure. In high doses can activate GABA receptors also.
Why don't Local anaesthetics generally work well in acidic environments such as in an abscess?
Because most Local anaesthetics are alkaline
Outline the three classes of pain fibres; what their sizes are and whether they are myelinated or not.
A fibres: Large diameter, with myelination
B fibres: Small diameter, with myelination
C fibres: Small diameter, unmyelination
Local anaesthetics will tend to work on which pain fibres more quickly? What might be the symptoms?
C fibres, due to its small diameter and unmyelination. Clinical findings include warm dry feet and vasodilation and hypotension
What are the two groups of Local anaesthetics and how do they work?
Antagonistic LAs: Block receptors, non-depolarising
Agonistic LAs: Activative receptors, strongly depolarising
Give 2 examples of Antagonistic Local anaesthetics and explain how they work
Tubocurare and Atracurium, which are NAChR antagonists preventing NMJ transmission
Reversal agents such as Neostigmine are given following what class of drugs? How does Neostigmine work?
Neostigmine is administered as a reversal agent for Antagonistic, non-depolarising LAs. Act as an Acetylcholinesterase inhibitor to increase ACh in the NMJ for longer
Give 1 example of Agonistic Local anaesthetic and explain how they work
Suxamethonium, which is a mimic for ACh, causing depolarisation across the NMJ