PHAR232 - Local anaesthetics

Question 1

What is the goal of local anaesthetics ?

Answer 1

Prevent nociceptive signals
Completely relax the muscle

Question 2

What are nomenclature structures derived from?

Answer 2

Cocaine

Question 3

Mechanism of action of local anaesthetics

Answer 3

KNOW THIS PATHWAY AND YOUTUBE

Question 4

Answer 4

Hydrophilic pathway - binding pocket most easily accessable when the channel is in use

Cannot go to inactive state until goes through active state

Question 5

For the hydrophilic pathway, binding site is best accessed when the channel is _________. Therefore hydrophilic local anaesthetic drugs referred to as __________________.

Answer 5

In use
Use-dependent

Question 6

If a drug binding via hydrophobic pathway use-dependent?

Answer 6

No

Question 7

What is anaesthetic action dependent on?

Answer 7

Normal actiity of nerve
- Lipid solubility of drug
- pH of tissue

Question 8

Mechanism of action

Question 9

Are local anaesthetics weak or strong pKa bases?

Answer 9

weak

Question 10

What is pKa?

Answer 10

50% molecule is ionised and 50% unionised
on a pH scale

Question 11

If you have a pKa of 8 - 14, are you ionised or unionised?

Answer 11

un-ionised

Question 12

If you have a pKa of 1 - 8, are you ionised or unionised?

Answer 12

ionised

Question 13

Do ionised drugs cross a membrane?

Answer 13

No - they are repelled

Question 14

Why are un-ionised drugs with a weaker pH base selected for anaesthetics and medications?

Answer 14

Un-ionised = weaker pH base
= easier to cross cell membrane

Question 15

Answer 15

systemic considerations of action
Drug needs to be confined - common to add a vasoconstrictor e.g. adrenaline

Question 16

Role of pH in relation to local anaesthetics

Answer 16

Key side effects for consideration

Question 17

KEY TOXICITY ISSUES - KNOW

Answer 17

Modes of delivery -
never inject into the nerve - will kill the nerve and leave them paralysed

Question 18

Infiltration anaesthesia

Answer 18

Field block anaesthesia

Question 19

Nerve block anaesthesia

Answer 19

Nerve plexus - sacral plexus
- DOnt nee to worry about pH or cellular membrane

Question 20

What is another term for intravenous regional anaesthesia?

Answer 20

Bier’s block

Question 21

IV regional anaesthesia

Answer 21

Traps blood at blessure, then releases the diaphram to enhance the area under anaesthia

Question 22

What is the goal of IV regional anaesthesia?

Answer 22

Use vasculature to transport drug
youtube to reconsolidate

Question 23

Window for use - generally 45 mins

Answer 23

SPINAL ANAESTHESIA

Question 24

Lumbar puncture

Question 25

KNOW WHY - STUDY THIS

Answer 25

Epidural anaesthesia

Question 26

Epidural space injections

Answer 26