Local Anaesthetics Flashcards
1
Q
Amides
A
-NH.CO- Lidocaine Bupivacaine Prilocaine Ropivacaine Mepivacaine
Undergo hepatic metabolism by amidases
Extensively bound to alpha 1 glycoprotein & albumin
2
Q
pKa
A
Procaine: 8.9 Amethocaine: 8.5 Cocaine: 8.6 Lidocaine: 7.9 Prilocaine: 7.7 Bupivacaine: 8.1 Ropivacaine: 8.1 Mepivacaine: 7.6
3
Q
Protein binding %
A
Procaine: 6 Amethocaine: 75 Cocaine: 95 Lidocaine: 70 Prilocaine: 55 Bupivacaine: 95 Ropivacaine: 94 Mepivacaine: 77
4
Q
Lipid Solubility (relative)
A
Procaine: 1 Amethocaine: 200 Cocaine: ? Lidocaine: 150 Prilocaine: 50 Bupivacaine: 1000 Ropivacaine: 300 Mepivacaine: 50
5
Q
Maximum dose (mg/kg)
A
Procaine: 12 Amethocaine: 1.5 Cocaine: 3 Lidocaine: 3 (7 with adrenaline) Prilocaine: 6 Bupivacaine: 2 Ropivacaine: 3.5 Mepivacaine: 5
6
Q
Relative potency
A
Related to lipid solubility Procaine: 1 Amethocaine: 8 Cocaine: ? Lidocaine: 2 Prilocaine: 2 Bupivacaine: 8 Ropivacaine: 8 Mepivacaine: 2
7
Q
Onset
A
Related to pKa Procaine: slow Amethocaine: slow Cocaine: medium Lidocaine: fast Prilocaine: fast Bupivacaine: medium Ropivacaine: medium Mepivacaine: slow
8
Q
Duration
A
Related to protein binding Procaine: short Amethocaine: long Cocaine: short Lidocaine: medium Prilocaine: medium Bupivacaine: long Ropivacaine: long Mepivacaine: medium
9
Q
Esters
A
-CO.O-
Procaine
Amethocaine
Cocaine
Rapidly hydrolysed by plasmacholinesterases and esterases to inactive compounds.
Para-aminobenzoic acid = allergen metabolite
Cocaine undergoes hepatic hydrolysis
10
Q
% unionised at pH 7.4
A
Procaine: ? Amethocaine: 7 Cocaine: 5 Lidocaine: 25 Prilocaine: 33 Bupivacaine: 15 Ropivacaine: 15 Mepivacaine: ?
11
Q
Elimination ½ life (min)
A
Procaine: ? Amethocaine: 80 Cocaine: 100 Lidocaine: 100 Prilocaine: 100 Bupivacaine: 160 Ropivacaine: 120 Mepivacaine: ?
12
Q
Vasodilator Activity
A
In low concentrations
Prilocaine > lidocaine > bupivacaine > ropivacaine
In high concentrations have vasoconstrictor activity
Cocaine purely vasoconstrictor (inhibits catecholamine uptake and inhibits MAO)
