Which metabolite is the biologically active liver metabolite of procainamide?

Which metabolite is the biologically active liver metabolite of procainamide?

• A. Phenobarbital
• B. Quinidine
• C. N-acetyl procainamide
• D. Lidocaine

Answer: (C)

The main idea is how procainamide is processed by the liver and which product remains pharmacologically active. Procainamide is transformed in the liver by acetylation to N-acetylprocainamide, often called NAPA. This metabolite still has antiarrhythmic activity and contributes to the overall effect and potential toxicity of therapy. The other substances listed are not products of procainamide metabolism—they are different drugs entirely (phenobarbital, quinidine, lidocaine). So, the biologically active liver metabolite of procainamide is N-acetylprocainamide.

The main idea is how procainamide is processed by the liver and which product remains pharmacologically active. Procainamide is transformed in the liver by acetylation to N-acetylprocainamide, often called NAPA. This metabolite still has antiarrhythmic activity and contributes to the overall effect and potential toxicity of therapy. The other substances listed are not products of procainamide metabolism—they are different drugs entirely (phenobarbital, quinidine, lidocaine). So, the biologically active liver metabolite of procainamide is N-acetylprocainamide.