A group of drugs which reversibly block sodium channels. When applied to nerves, they prevent the propagation of the action potential causing anaesthesia in the distribution of the nerve, and motor blockade affecting any supplied muscles.
Local Anaesthetic Toxicity is the unwanted systemic effects of local anaesthetic agents. These may be caused by inadvertent intravascular injection, or relative overdosage.
Sodium channels are present in many tissues therefore systemic local anaesthetics cause generalised tissue depression. Signs include: hypotension (direct cardiac depression, CVS centre depression and autonomic depression); bradycardia, heart block and asystole (depression of the cardiac conducting system); confusion and coma (CNS depression) and seizures (depression of inhibitory neuronal structures).
Management of toxicity is ABC, plus the management of the above signs, and may include: atropine, vasopressors, anticonvulsants, airway protection, respiratory support, and the management of cardiac arrest.
The original amide local anaesthetic, introduced in 1944. A significant improvement over the esters which preceded it. Now called Lidocaine (US international).
