[Nephrotoxicity after the use of intravenous X-ray contrast media in a type 2 diabetic being treated with metformin].

Contrast media may induce nephrotoxicity, particularly in elderly patients with pre-existing renal impairment. The concomitant use of metformin may lead to lactic acidosis due to metformin accumulation. Thus, metformin should be discontinued prior to use of contrast media. We observed acute renal failure requiring haemodialysis in a 74-year-old man with non-insulin-dependent type II diabetes. The man had had an intravenous urography to examine an increased plasma creatinine level, and metformin had not been discontinued. We report the case to remind doctors of this avoidable side effect.