What is the active metabolite of the antiarrhythmic drug procainamide?

What is the active metabolite of the antiarrhythmic drug procainamide?

• A. Pronestyl
• B. Disopyramide
• C. PEMA
• D. NAPA

Answer: (D)

Procainamide is metabolized in the liver to an active compound called N-acetylprocainamide, abbreviated as NAPA. This metabolite continues to exert antiarrhythmic effects, primarily by blocking sodium channels, and it can also have potassium channel–blocking activity that contributes to prolonging the action potential. Because NAPA often has a longer half-life than the parent drug, it can accumulate, especially in slow acetylators or with renal impairment, influencing both efficacy and risk of toxicity. Therefore, the active metabolite of procainamide is NAPA (N-acetylprocainamide).

Procainamide is metabolized in the liver to an active compound called N-acetylprocainamide, abbreviated as NAPA. This metabolite continues to exert antiarrhythmic effects, primarily by blocking sodium channels, and it can also have potassium channel–blocking activity that contributes to prolonging the action potential. Because NAPA often has a longer half-life than the parent drug, it can accumulate, especially in slow acetylators or with renal impairment, influencing both efficacy and risk of toxicity. Therefore, the active metabolite of procainamide is NAPA (N-acetylprocainamide).