Lidocaine/Lignocaine

• Class: Local anesthetic (Class 1B) antiarrhythmic
• Action: It acts by combining with fast Na+ channels when inactive which inhibits recovery after repolarization. Lidocaine alters signal conduction in neurons by blocking the fast voltage gated Na+ channels in the neuronal cell membrane, which are responsible for signal propogation. With sufficient blockade, the membrane of the postsynaptic neuron will not depolarize and so fail to transmit an action potential, leading to its anaesthetic effects. At therapeutic levels, it causes phase 4 diastolic depolarization attenuation, decreased automaticity, and either a decrease or no change in membrane responsiveness and excitability. These effects will occur at serum levels that will not inhibit the automaticity of the SA node, and will have little effect on AV node conduction or His-Purkinje conduction.
• Indications: Infiltration anaesthesia, surface anaesthesia, nerve block, epidural anaesthesia, regional anaesthesia, Arrhythmia associated with general anaesthesia
• Dosage:               IV

               Dog: 2 - 4 mg/kg given slowly as IV bolus followed by 25 - 100 mcg/kg/min