W19/L5: Anaesthetics Flashcards
How do local anaesthetic agents work?
They interfere with Na+ influx to block action potentials in sensory nerves
What’s an example of an aminoester anaesthetic?
Procaine
What’s the duration of action of aminoesters like?
Relatively short ~30min
Why do aminoesters have a short duration of action
they’re hydrolysed by esterases (including AChE)
List 3 examples of aminoamide anaesthetics
Lignocaine
Bupivicaine
Ropivicaine
Why are the aminoamide anaesthetics longer acting?
They’re metabolised hepatically
What’s the local anaesthetic that doesn’t have a family?
Benzocaine
What features of local anaesthetics make them safe?
They bind reversibly
There’s no permanent nerve damage
They are administered in a way that limits systemic distribution
Describe the neural Na+ channel
Large protein with many TM domains.
Has two gates: M- and N-gate
Where on the Na+ channel do toxins usually bind?
On the extracellular side - usually causing complete & irreversible blockage.
Where on the Na+ channel do the local anaesthetics bind?
On the intracellular side
What are the two mechanisms of local anaesthetics interacting with the Na+ channel?
Hydrophobic and hydrophilic
How does the hydrophobic MoA of local anaesthetics work?
The drug in its uncharged form can enter the cell membrane and take position in the Na+ pore
*Skip the rest of this cause I think JZ’s explanation is wrong. Look it up!
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What are the commonly inhaled GAs?
Desflurane
Sevoflurane
Isoflurane