Biopsy proven acute interstitial nephritis after treatment with moxifloxacin

BACKGROUND Acute interstitial nephritis (AIN) is an important cause of reversible acute kidney injury. At least 70% of AIN is caused by various drugs, mainly penicillins and non-steroidal anti-inflammatory drugs. Quinolones are only rarely known to cause AIN and so far cases have been mainly described with older fluoroquinolones. CASE PRESENTATION Here we describe a case of biopsy proven interstitial nephritis after moxifloxacin treatment. The patient presented with fever, rigors and dialysis dependent acute kidney injury, just a few days after treatment of a respiratory tract infection with moxifloxacin. The renal biopsy revealed dense infiltrates mainly composed of eosinophils and severe interstitial edema. A course of oral prednisolone (1 mg/kg/day) was commenced and rapidly tapered to zero within three weeks. The renal function improved, and the patient was discharged with a creatinine of 107 micromol/l. CONCLUSION This case illustrates that pharmacovigilance is important to early detect rare side effects, such as AIN, even in drugs with a favourable risk/benefit ratio such as moxifloxacin.