Which statement about N-acetylprocainamide is true?

Which statement about N-acetylprocainamide is true?

• A. It is the major active metabolite used for monitoring procainamide therapy.
• B. It is an inactive metabolite.
• C. It is a liver enzyme.
• D. It is excreted unchanged.

Answer: (A)

N-acetylprocainamide is the major active metabolite formed from procainamide in the liver, and it retains antiarrhythmic activity. Its effect and often longer half-life mean that measuring its level provides a better indication of the drug’s overall pharmacologic impact and toxicity risk, so it’s used for monitoring procainamide therapy (often alongside procainamide levels). The other statements aren’t correct because NAPA is not inactive, it is not a liver enzyme, and the drug is not excreted unchanged—the metabolite is mainly eliminated renally, which is why renal function influences its levels.

N-acetylprocainamide is the major active metabolite formed from procainamide in the liver, and it retains antiarrhythmic activity. Its effect and often longer half-life mean that measuring its level provides a better indication of the drug’s overall pharmacologic impact and toxicity risk, so it’s used for monitoring procainamide therapy (often alongside procainamide levels). The other statements aren’t correct because NAPA is not inactive, it is not a liver enzyme, and the drug is not excreted unchanged—the metabolite is mainly eliminated renally, which is why renal function influences its levels.