LAs

Question 1

Ester LA

Answer 1

procaine - poor tissue penetration, short half life

Question 2

Amide LA

Answer 2

lidocaine/lignocaine - metabolised by n-dealkylation in liver - longer half life

Question 3

Unexpected LAs at high concs (non specific)

Answer 3

morphine and propranolol

Question 4

Atypical LAs

Answer 4

Benzocaine - no amino group, always unprotonated, only works through hydrophobic pathway

QX314 - always protonated, used experimentally, has to be introduced into cell

Question 5

Prolonging agent for LA

Answer 5

vasoconstrictor e.g adrenaline

Question 6

Less vasodilatation

Answer 6

mepivicaine

Question 7

cardiotoxicity

Answer 7

bupivicaine

Question 8

can induce paraesthesia

Answer 8

articaine (dentistry)

Question 9

spinal block (surgery of abdomen/pelvis/leg)

Answer 9

bupivicaine (long duration, less doses needed)
lignocaine
tetracaine

into subarachnoid space

Question 10

surface anaesthesia (e.g. topical,corneal surgery)

Answer 10

tetracaine, lignocaine

Question 11

infiltration anaesthesia

Answer 11

most, often with adrenaline, never in peripheries

Question 12

I.V. regional e.g. limb surgery (use torniquet)

Answer 12

lignocaine, prilocaine

Question 13

I.V. for neuropathic pain

Answer 13

lignocaine

Question 14

nerve block (trunk/plexus)

Answer 14

most LAS