local anaesthesia
Last reviewed 01/2018
Lignocaine is widely used as a local anaesthetic. It can be combined with adrenaline to reduce bleeding; this is advantageous for face and scalp surgery. It has a rapid onset. Ischaemia may result if lignocaine with adrenaline is used on peripheries such as the ear or digits.
The half-life of lignocaine is two hours. The maximum dose of lignocaine is 200mg on its own or 500mg when combined with adrenaline. The maximum volume permissible is thus calculated knowing the concentration of regular solutions:
- 0.5% = 5mg/ml
- 1% = 10mg/ml
- 2% = 20mg/ml
Overdosage of lignocaine can result in convulsions, twitching and psychosis.