A case of cimetidine-induced acute tubulointerstitial nephritis associated with antineutrophil cytoplasmic antibody.

We present a case of acute tubulointerstitial nephritis (ATIN) that developed in a 63-year-old man who had been taking cimetidine for treatment of a gastric ulcer. The constellation of clinical, laboratory, and histopathologic findings suggested drug-induced ATIN. Of interest, the patient had antineutrophil cytoplasmic antibody (ANCA) in his sera, reactive with myeloperoxidase, elastase, and lactoferrin. Prominent renal histological features included marked plasmacyte infiltration into the renal interstitium. Withdrawal of cimetidine resulted in complete resolution of renal findings, and the titers of ANCA concomitantly declined. Thus, cimetidine may have played a causative role in the development of ANCA-associated ATIN.