Suspected acute interstitial nephritis induced by colistin.

We describe a 35-year-old male admitted to the intensive care unit (ICU) for acute exacerbation of chronic obstructive pulmonary disease (COPD). He developed ventilator-associated pneumonia caused by multidrug-resistant Pseudomonas aeruginosa and was treated with imipenem and colistin without any renal toxicity. The patient was readmitted to the ICU for a 2nd and a 3rd exacerbation of COPD and was again treated with imipenem and colistin. In both episodes, he developed rapid worsening in renal function, which improved following colistin withdrawal. Use of the Naranjo ADR probability scale indicated a probable relationship between the renal failure and the colistin therapy. In addition, the time course of events suggested that colistin was the cause of acute interstitial nephritis in this patient. We conclude that our patient had a possible acute allergic reaction to colistin since the 1st introduction was not associated with any renal toxicity and renal failure was observed on the 1st day of the 2nd and the 3rd initiation of colistin therapy, respectively.