MCQ MAHE 2000 Pharmacology Answer 04

The Correct Answer is A

Moricizine is a is a phenothiazine derivative Vaughan Williams class I antiarrhythmic agent with potent local anesthetic activity and myocardial membrane stabilizing effects. Moricizine reduces the fast inward current carried by sodium ions.

Decreases excitability, conduction velocity, and automaticity as a result of slowed atrioventricular (AV) nodal and His-Purkinje conduction. Decreases the action potential duration (APD) in Purkinje fibers; also decreases the effective refractory period (ERP) but to a lesser extent than the APD, so the ERP/APD ratio is increased. Decreases the maxiumum rate of Phase 0 depolarization (V max ), but does not affect action potential amplitude or maximum diastolic potential.

In the Vaughan Williams classification of antiarrhythmics, moricizine is considered to be a class I agent. It has properties of class IA, IB, and IC agents but does not clearly belong to any of the three subclasses. It has less effect on the slope of phase 0 and a greater effect on action potential duration and effective refractory period than class IC agents.

Category: MAHE 2000 MCQs