Nephrotoxicity of interferon alfa-ribavirin therapy for chronic hepatitis C

The nephrotoxicity associated with interferon therapy for chronic hepatitis C infection has not been clearly defined. We describe a patient with chronic hepatitis C infection who developed the nephrotic syndrome during treatment with interferon and ribavirin. Renal biopsy revealed focal segmental glomerulosclerosis. She had a virologic and biochemical response to the antiviral therapy, and the nephrotic syndrome improved after termination of antiviral therapy. We place our case report in context with a review of the literature on nephrotoxicity associated with interferon therapy. Because our patient had no other obvious reason for the nephrotic syndrome, we are postulating that it may be secondary to interferon-ribavirin therapy. The temporal relation between the administration of the drug and the detection of toxic affects (nephrotic syndrome) and subsequent improvement upon withdrawal also supports a causative role for interferon-ribavirin. Although nephrotoxicity is rare, it should be emphasized that it can occur anytime after the start of interferon therapy, and physicians treating patients with chronic hepatitis C must be aware of this idiosyncratic, unpredictable, and potentially serious adverse event.