Which class includes Lidocaine?

Which class includes Lidocaine?

• A. Type 1A
• B. Type 1B
• C. Type 2
• D. Type 3

Answer: (B)

In antiarrhythmic pharmacology, drugs are sorted by how they affect cardiac sodium channels and the action potential. Lidocaine is a sodium channel blocker that fits into the class known as IB. These blockers have rapid on/off kinetics and preferentially affect depolarized or ischemic tissue, such as ventricular myocardium, while sparing normal tissue. They tend to shorten the action potential duration in the areas they target, which helps suppress ventricular ectopy and certain ventricular tachyarrhythmias. That’s why lidocaine is placed in this group: its main action as an antiarrhythmic is the quick, use-dependent blockade of fast sodium channels, with effects distinct from other classes. For context, other classes work differently—some gently slow conduction and prolong the action potential (the IA group), others are beta blockers (slowing heart rate and conduction via adrenergic pathways), and others prolong repolarization by blocking potassium channels (the III group). The specific profile of lidocaine aligns with the class that emphasizes rapid, tissue-selective sodium channel blockade.

In antiarrhythmic pharmacology, drugs are sorted by how they affect cardiac sodium channels and the action potential. Lidocaine is a sodium channel blocker that fits into the class known as IB. These blockers have rapid on/off kinetics and preferentially affect depolarized or ischemic tissue, such as ventricular myocardium, while sparing normal tissue. They tend to shorten the action potential duration in the areas they target, which helps suppress ventricular ectopy and certain ventricular tachyarrhythmias.

That’s why lidocaine is placed in this group: its main action as an antiarrhythmic is the quick, use-dependent blockade of fast sodium channels, with effects distinct from other classes. For context, other classes work differently—some gently slow conduction and prolong the action potential (the IA group), others are beta blockers (slowing heart rate and conduction via adrenergic pathways), and others prolong repolarization by blocking potassium channels (the III group). The specific profile of lidocaine aligns with the class that emphasizes rapid, tissue-selective sodium channel blockade.