Tenofovir-induced Fanconi syndrome in chronic hepatitis B monoinfected patients that reverted after tenofovir withdrawal

•Tenofovir (TDF) is increasingly used to treat CHB patients worldwide.•We describe two cases of TDF-induced Fanconi syndrome in CHB patients.•Fanconi syndrome reverted after TDF withdrawal while HBV was suppressed by ETV.•Glomerular and tubular function should be carefully monitored in patients under TDF.•Several factors, including age and ADV exposure, may increase the risk of this complication. Tenofovir disoproxil fumarate (TDF) is a nucleotide reverse transcriptase inhibitor widely used to treat patients with human immunodeficiency virus (HIV) and hepatitis B virus (HBV) infection. Despite the excellent safety records of this regimen, a few cases of acute renal failure and Fanconi syndrome have been reported among HIV patients exposed to TDF. In the HBV monoinfection scenario, only two cases of TDF-associated Fanconi syndrome have been reported thus far. Here, we describe two additional patients with chronic hepatitis B (CHB) who developed a TDF-induced Fanconi syndrome that reverted after TDF withdrawal and had viral replication fully suppressed upon switching to entecavir (ETV). Though the overall risk of TDF associated severe renal toxicity in HBV patients appears to be negligible, both glomerular and tubular function should be monitored in patients exposed to TDF, especially when other renal risk factors or a history of previous exposure to adefovir dipivoxil (ADV) are present.