Fanconi syndrome due to prolonged use of low-dose adefovir

Fanconi syndrome results from a generalized abnormality of the proximal tubules of the kidney and owing to phosphate depletion can cause hypophosphatemic osteomalacia. Adefovir dipivoxyl (ADV) effectively suppresses hepatitis B virus replication but exhibits nephrotoxicity when administered at a low dosage. We report two cases of Fanconi syndrome induced by ADV at 10 mg/day to call for regular screening for evidence of proximal tubular dysfunction and detailed bone metabolic investigations for prompt detection of ADV nephrotoxicity is critically important to ensure timely drug withdrawal before the development of irreversible tubulointerstitial injury.