Drug-induced hepatotoxicity linked to zoledronic acid in the treatment of an elderly man with primary osteoporosis

Zoledronic acid (ZA), an intravenous bisphosphonate, has been widely used for the treatment of osteoporosis. ZA is generally well tolerated, and ZA-related hepatotoxicity is rare. We report a case of hepatotoxicity after ZA infusion in an elderly male patient with primary osteoporosis. The patient had femoral neck and vertebral fractures, and 3 days after ZA 5-mg infusion, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) increased 23.4- and 15.3-fold, respectively, compared with pre-treatment values. Hepatoprotective agents were administered, and liver enzymes were back to near normal range 9 days later. This case report shows the possible hepatic adverse effects related to ZA infusion. The mechanism of hepatotoxicity caused by ZA is not clear. Acute-phase reaction after ZA infusion may play a role in hepatotoxicity, which should be taken into consideration, especially for the elderly.