Cimetidine-induced acute interstitial nephritis.

Cimetidine is responsible for changes in serum creatinine. Previously reported, this has been thought to be related to an alteration in the manner in which the kidney handles creatinine. Herein a case of acute interstitial nephritis attributable to the ingestion of routine doses of cimeditine is detailed. Review of the changes in serum creatinine and renal function in patients taking cimetidine reveals that as many as 60% of the patients taking cimetidine may have changes in serum creatinine. In none of those series, however, have changes in urinary protein excretion or urinary sediment been followed. Recently several reports have been published in which patients have developed acute interstitial nephritis while taking cimetidine. However, in no previously reported case has the diagnosis been proved by rechallenging the patient with that drug. In our study the patient had moderate to severe renal insufficiency with acute interstitial nephritis while on cimetidine. Rechallenging the patient with cimetidine resulted in prompt return of clinical signs and symptoms as well as changes in serum creatinine and urinary sediment characteristics diagnostic of interstitial nephritis.