Local Anaesthetic: Revised & Condensed

Question 1

Tissues that have the greatest to least vascularity for LA?

Answer 1

BICEPSS

Blood/Tracheal
Intercostal
Caudal and para “cervical”
Epidural
Perivascular brachial plexus
Sciatic/Spinal
Subcutaneous

From notes

IV > tracheal > intercostal > caudal > epidural > brachial > sciatic > s.c

Question 2

Esters Metabolised?

Answer 2

Plasma cholinesterase’s to
inactive compounds

Question 3

Amides Metabolism?

Answer 3

In liver hepatic cytochromes

CYP450

Question 4

In which form is LA in its ionised form?

Answer 4

Water solubility of a LA is greatest in its ionised form

Question 5

How are La injectable preparations formulated as?

Answer 5

Injectionable preparations are formulated as HCL salts

Question 6

How do you increase speed of action?

Answer 6

Increasing alkalinity of injection solution increases the speed of action

Question 7

La Systemetic toxicity?

Answer 7

SAMS

Slurred Speech(Parathesis)
Altered Central Nervous System(Arrhythmias)
Muscle Twitching(Tremors)
Seizures(Respiratory & cardiac arrest)

1. Slurred Speech(Parathesis)
   -Parathesias
   -Numbness of lips/tongue
2. Altered Central Nervous System(Arrhythmias)
   -Drowsiness
   -Dizziness
   -Arrhythmias
   -Restlessness
   -Confusion
3. Muscle Twitching
   -Tremors
4. Seizures
   -Respiratory & cardiac arrest
   -Convulsions
   -Respiratory depression
   -Respiratory and cardiac arrest

Question 8

What is the treatment for LA induced seizures?

Answer 8

Benzodiapines thiopentone

Question 9

What is the treatment for LA induced reduced level of consciousness?

Answer 9

Oxygen

Question 10

What is the treatment for LA induced hypotension?

Answer 10

Vasopressors
-Ephedrine/Phelephrine
-Inotropes/Adrenaline

Question 11

What is the treatment for LA induced ventricular fibrilation?

Answer 11

Intralipid infusion

Question 12

How to prevent LA toxicity?

Answer 12

 Use max safe dose
 Aspirate regularly during injection
 Adrenaline if appropriate
 Test doses
 Stabilise needle carefully
 Monitor patients vitals

Question 13

Infiltration LA?

Answer 13

Infiiltration in the RMBL

Ropivacaine
Mepivacine
Bupivacaine
Lignocaine

Question 14

Bupivacaine

Ester/Amide
P/K(LA & DOA)
I
M
Toxcity

Answer 14

Amide

P/K:Long-acting LA {doa usually 3 hours, peripheral blocks: 2-24hrs: dose & site}


I: Local infiltration, regional block, spinal & epidural anaesthesia
Chiefly used for surgical anaesthesia

M: Liver

Toxcity: Cardiotoxic

Question 15

Which drug has a better CV safety profile then bupivacaine?

Answer 15

Levobupivacaine
-S-enantiomer of bupivacaine

Question 16

Lignocaine

Ester/Amide
P/K(LA & DOA)
I
M
DI

Answer 16

Amide

Indications:
-Mostly used in dental practise
- Local/topical
- Infiltration
- Intravenous regional anaesthesia (biers block)
- Epidural anaesthesia

P/K: Rapid onset of action & Intermediate duration

CI:
Heart block/conduction disturbances

M: Liver hepatic Cytpchromes

DI: Cimetidine/Beta Blockers & NMB

Question 17

Ropivacaine

Duration
Cautions
Indications
Metabolism

Answer 17

D: Long-acting LA

C: partial or complete
heart block, elderly, liver dysfunction

I: Epidural anaesthesia, local nerve block, infiltration & analgesia

M: Liver enzymes

Question 18

Mepivacaine

Uses
Duration of action
Indications

Answer 18

Uses: Used in dental practice
DOA: Intermediate acting
Indications: Infiltration and nerve blocks
Metabolism: Liver Enzymes

Question 19

Peripheral Nerve Blocking LA’s?

Answer 19

RMBL

Ropivacaine
Mepivacaine
Bupivacaine
Lignocaine

Question 20

Central Nerve Block?

Answer 20

RBL

Ropivacaine
Bupivacine
Lignocaine

Question 21

Articaine

Amides/Ester?
Indications?
P/K?
Solubility?
Uses?
Frequency of formulation?

Answer 21

Amides

I: Infiltration & Nerve Blocks

P/K: Amide but with ester side chain, High lipid solubility, Rapid onset

Uses: Dental & Periodontal

Question 22

Ester drugs & M?

Answer 22

BOT ( Esther is a beaut/BOT)

Benzocaine
Oxybuprocaine
Tetracaine

M: Plasma cholinesterase

Question 23

Amide drugs & M?

Answer 23

LAB MRP

Lignocaine
Atricaine
Bupicaine
Mepivacine
Ropivacine
Prilocaine

M: CYP450 Liver Cytochrome

Question 24

Topical Anaesthesia?

BOLT P

Answer 24

Benzocaine
Oxybuprocaine
Lignocaine
Tetracaine

Prilocaine

Question 25

Prilocaine is avaliable with which drug?

Answer 25

Lignocaine

Question 26

Prilocaine Admin?

Answer 26

Cream & Patch

Question 27

Lignocaine Admin?

Answer 27

 Topical spray: larynx
 Jelly: urethral anaesthesia &
haemorrhoids
 Patch: (5%, S4) neuropathic
pain relief (PHN

Question 28

Oxybuprocaine uses and additional activity?Uses:

Answer 28

Oxybuprocaine uses and additional activity?Uses:
 Eye drops: ophthalmology in
tonometry, foreign body removal,
suture removal
 Has additive bactericidal activity

Question 29

Tetracaine Admin?

Answer 29

Topical cream: pain relief in
haemorrhoids and minor skin burns

 Eye drops: ophthalmology in
tonometry, foreign body removal,
suture removal

 Oral gel: pain relief of mucous
membranes of mouth, lips, gums

Question 30

Benzocaine Admin?

Answer 30

Topical gel: dentistry injection
sites: minimize sensation

 Lozenge: Surface anaesthetic -
pain relief of sore throats

 Throat spray

Throat gargle

Question 31

Explain the drug interactions of cimetidine and beta blockers?

Answer 31

Cimetidine:
-CYP450 Inhibitor
-Binds cardiac sodium channels during diastole and its metabolism is inhibited

Beta-blockers:
-Decreases metabolism of lignocaine & increased duration in body causes toxicity
-