Metronidazole and Tacrolimus Interaction in a Kidney Transplant Recipient

We present a 56-year-old male kidney transplant recipient who was hospitalized for acute kidney injury due to gastroenteritis related volume depletion and had kindey function deterioration secondary to rising plasma levels of tacrolimus after metronidazole administration. Tacrolimus dose was decreased and arranged daily by closely drug level monitoring. His creatinine value returned to his basal levels after metronidazole was stopped and his tacrolimus levels were kept in target range. Tacrolimus is metabolized primarily in the liver by CYP3A enzymes and drugs that affect CYP3A functions such as metronidazole can cause elevated tacrolimus plasma levels that results in nephrotoxicity. This case teach us that calcineurin inhibitors should be closely monitored in kidney transplant recipients during metronidazole treatment.