A. Class Ia.
B. Class Ib.
C. Class Ic.
D. Class III.
Ans:B. Class Ib type.
Lidocaine is an antiarrhythmic medication of the class Ib type.
Types of Antiarrhythmic medicines:
Class I: Fast sodium (Na) channel blockers
- Ia – Quinidine, procainamide, disopyramide (depress phase 0, prolonging repolarization)
- Ib – Lidocaine, phenytoin, mexiletine (depress phase 0 selectively in abnormal/ischemic tissue, shorten repolarization)
- Ic – Flecainide, propafenone, moricizine (markedly depress phase 0, minimal effect on repolarization)
Class II: Beta blockers
- Propranolol (decreases slope of phase 4)
- Esmolol (decreases slope of phase 4)
- Timolol (decreases slope of phase 4)
- Metoprolol (decreases slope of phase 4)
- Atenolol (decreases slope of phase 4)
Class III: Potassium (K) channel blockers
- Amiodarone (prolongs phase 3; also acts on phases 1, 2, and 4)
- Sotalol (prolongs phase 3, decreases slope of phase 4)
- Ibutilide (prolongs phase 3)
- Dofetilide (prolongs phase 3)
Class IV: Slow calcium (Ca) channel blockers
- Verapamil (prolongs phase 2)
- Diltiazem (prolongs phase 2)
Class V: Variable mechanism
- Magnesium sulfate