How long after removing the offending agent in suspected drug-induced acute interstitial nephritis does creatinine typically begin to improve?

• A. 3-7 days.
• B. 1 day.
• C. 2-3 weeks.
• D. No improvement.

Answer: (A)

Stopping the offending drug halts ongoing interstitial inflammation, allowing the kidney to begin healing. In drug‑induced acute interstitial nephritis, creatinine levels typically start to improve within a few days after withdrawal, commonly in the 3–7 day window. Early improvement within 24 hours is unlikely because the inflammatory process needs time to subside, and waiting several weeks for initial improvement is longer than usual. Remember, full recovery can continue over weeks, and if there’s no meaningful improvement after several days, further evaluation and possible therapy may be needed.