Fatal lactic acidosis associated with the use of combination oral medications to treat reactivation of hepatitis B.

Oral nucleos(t)ide analogs for the treatment of hepatitis B virus (HBV) infection are well tolerated with minimal side effects. These agents do carry a Food and Drug Administration "black box" warning about the development of fatal lactic acidosis on the basis of data from the human immunodeficiency virus literature. However, no previously published cases of this lethal side effect have been reported in patients undergoing HBV treatment using the current Food and Drug Administration-approved HBV medications. We report a case of HBV reactivation after chemotherapy for leukemia, and the development of fatal lactic acidosis attributed to the use of combination oral HBV medications.