LA agents Flashcards
1
Q
List the agents used in LA
A
- Buffering agents
- Preservatives
- Sodium chloride
- Sodium hydroxide
- Antioxidants
2
Q
Describe buffering agents
A
- Sodium hydroxide, hydrochloric acid and EDTA etc may be added to adjust the pH of the solutions (especially if adrenaline present)
- pH of plain solutions adjusted to between 4-7
- pH is a prime factor in the burning sensation of LA
3
Q
Describe antioxidants
A
- Sodium metabisulfite
- Prevents oxidation of vasoconstrictor/ adrenaline
- Also tends to lower the pH
4
Q
State the role of sodium chloride
A
Adjust solution to make it isotonic
5
Q
State the role of sodium hydroxide
A
Adjust pH
6
Q
What is the half life of lignocaine?
What other LA agents share this half life?
A
Half life:
1.5 - 1.8 hrs
- Prilocaine
- Articaine
7
Q
What is the half life for mepivacaine?
A
2 - 3 hrs
8
Q
What is the duration AND half life for bupivacaine?
A
Duration:
12+ hrs
Half life:
1.5 - 5.5 hrs
9
Q
What is the amount of LA in Xylocaine?
A
5% lignocaine
10
Q
What is the amount of LA in oraqix and EMLA creams?
A
1:1 ratio of lignocaine and prilocaine
11
Q
Which LA drugs are metabolised in the liver?
A
- Lignocaine
- Mepivacaine
- Articaine (5% only)
- Prilocaine
12
Q
Which LA drugs are metabolised in plasma cholinesterases?
A
- Articaine (95%)
- Bupivacaine
- Procaine
