In this case of drug-induced interstitial nephritis, there are some scattered eosinophils, along with neutrophils and mononuclear cells in the inflamed interstitium. The classic example of this occurs occasionally with the antibiotic methicillin, but can occur with a variety of drugs such as thiazide diuretics and the H2 blocker cimetidine. The immune mechanism may be either type I or type IV hypersensitivity.

Question: What drugs may be associated with AIN?

AnswerThe best known cause for AIN is the antibiotic methicillin. Other penicillins and cephalosporins may also be implicated. Any of the NSAIDS, furosemide, thiazides, allopurinol, cimetidine, and sulfonamides can also cause AIN.