This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anesthesia, Subject name: Pharmacology
[{'content': 'All of the following statements about lignocaine are true except \nSelect and explain. \nA. It blocks active sodium channels with more affinity than resulting sodium channels, B. It can cause cardiotoxicity, C. It is given orally for treatment of cardiac arhymias, D. Adrenaline increases the duration of action of lignocaine when used for infiltration anesthesia', 'role': 'user'}, {'content': 'Answer: C \nExplanation: All local anesthetics are weak bases.These drugs act by penetrating the axonal membrane and blocking the voltage gated sodium channels within Vasoconstrictors like adrenaline can prolong the duration of action. All LA can cause cardiotoxicity and neurotoxicity', 'role': 'assistant'}]