Fanconi syndrome caused by low-dose adefovir dipivoxil

Abstract

Adefovir dipivoxil (ADV) at a low-dose (10 mg daily), which was previously considered not nephrotoxic, was reported to have induced acquired Fanconi syndrome (FS). We report one 64-year-old Chinese woman and 2 Chinese men (ages 45 and 63 years) with bone pain, and/or muscle weakness on ADV therapy were diagnosed with low-dose ADV-induced FS. The serum phosphate normalized, or nearly normalized in the first and second patients after changing ADV to entecavir with, or without phosphate supplement, but did not improve significantly in the third patient after changing ADV to tenofovir, even though he was supplied with a higher dose of phosphate. Low-dose ADV-related FS is not rare in the Asian population. Regular monitoring of urine and serum phosphate is necessary during therapy with ADV. Prognosis was favorable, however, tenofovir is not a suitable replacement for ADV.