LOCAL ANAESTHETICS

All local anesthetic drugs:

• Are potentially toxic, you must know the maximum safe dose
• May depress the central nervous system
• May cause drowsiness, which may progress to unconsciousness with twitching and possibly convulsions
• May cause hypotension related to extensive sympathetic blockade or direct depression of cardiac function.
• These reactions are most likely to occur if the drug is accidentally injected into a vein or if an overdose is
  given by using either too high a concentration or too large a volume of drug.

LOCAL ANAESTHESIA

Rate of drug absorption can be reduced by injection with a vasoconstrictor drug, such as:

- epinephrine

• most often used in dilution of 5 mg/ml (1:200 000)
• for infiltration, 2.5 mg/ml (1:400 000) generally sufficient

To make a 1:200 000 dilution of epinephrine (adrenaline):

- add 0.1 ml of 1:1000 epinephrine to 20 ml local anaesthetic solution

Pre-mixed ampoules of local anaesthetic, epinephrine often available