Local Anaesthetics Flashcards
Give 2 examples of local anaesthetics
- Lidocaine (also known as lignocaine)
- Bupivacaine
What is the mechanism of action of local anaesthetics?
- Reversibly blocks Na channels to prevent neurotransmission
- Causes vasodilatation of arteries
What might the addition of adrenaline to local anaesthetics do?
Prolong anaesthetic effects (as it is a vasoconstrictor)
idgi
What do you need to be careful of not doing when injecting local anaesthetic?
Injecting LA mixed with adrenaline into organs with end-artery blood supply
What is the route of delivery of local anaesthetic?
- Topical
- IV
- Epidural
How should the dose of local anaesthetic ideally be calculated?
For non-emergency indications, using ideal body weight
What may be used when local anaesthetic is used topically?
Occlusive dressing
What are the indications for local anaesthetics?
- Local anaesthetic for procedures
- Treatment and prevention of ventricular tachycardia and ventricular fibrillation post-MI
- Surface and infiltration anaesthesia, nerve blocks, and epidural blocks
When are local anaesthetics contraindicated?
- Severe myocardial depression
- Sinoatrial disorders
- AV block
When should lidocaine be avoided?
Pregnancy
Why should lidocaine be avoided in pregnancy?
Cause neonatal bradycardia, and, following large doses, respiratory and CNS depression
What should be done when local anaesthetic is given in low cardiac output states?
Dose reduction
How can it be ensured local anaesthetic is effective?
Sensation can be tested by touching the area where the local anaesthetic has been used with the needle tip and asking the patient if the area feels numb or sharp
What might interact with local anaesthetics?
Adrenaline
What might happen if local anaesthetics are given with adrenaline?
Prolongs anaesthetic effects - but this is usually good so pretty nothing interaction lol
