Sodium channel blocker / LAST

Common Na⁺-channel blockers: local anaesthetics (LA — bupivacaine, levobupivacaine, ropivacaine, lidocaine), Class Ic antiarrhythmics (flecainide, propafenone), Class Ia (quinidine, procainamide, disopyramide), TCAs (separate pathway), cocaine, propranolol (non-selective β-blocker also blocks Na⁺), diphenhydramine. Features: • CNS: peri-oral tingling, tinnitus, metallic taste, agitation, seizures, coma. • Cardiac: wide QRS, terminal R wave in aVR ≥3 mm, AV block, VT/VF, asystole; bupivacaine particularly cardiotoxic. ABCDE; continuous ECG; 12-lead ECG within 10 min; bloods: VBG, U&E, glucose, paracetamol/salicylate, lactate.