ABSTRACT
Adefovir dipivoxil, an acyclic nucleoside analogue, has been approved for the treatment of patients with chronic hepatitis B. This agent is efficacious particularly in those who have developed lamivudine resistance. The report according to hypophosphatemia induced by low dose adefovir therapy is very rare. We report one case in which osteomalacia with hypophosphatemia developed in a patient with chronic hepatitis B on adefovir dipivoxil at a low dose, 10 mg daily. A 66-year-old man, who had been taking adefovir for more than 4 years due to lamivudine resistance, presented with muscle weakness and bone pain in both thighs. After 3 years of adefovir therapy, hypophosphatemia and elevated serum alkaline phosphatase levels had been noted. A bone scan showed multiple hot uptakes. All the image findings and clinical symptoms, such as bone pain and muscle weakness were improved after correcting the hypophosphatemia with oral phosphorous supplementation.
Subject(s)
Aged , Humans , Male , Adenine/adverse effects , Alkaline Phosphatase/blood , Antiviral Agents/adverse effects , DNA, Viral/blood , Dietary Supplements , Hepatitis B, Chronic/drug therapy , Hypophosphatemia/chemically induced , Liver Cirrhosis/diagnosis , Osteomalacia/diagnosis , Phosphates/blood , Phosphorous Acids/adverse effects , Whole Body ImagingABSTRACT
Adefovir dipivoxyl (ADV) effectively suppresses hepatitis B virus (HBV) replication but exhibits nephrotoxicity with severe hypophosphatemia when administered at a high dosage. This is the first report of severe hypophosphatemic osteomalacia induced by ADV at 10 mg/day. A 42-year-old man with HBV-related chronic liver disease presented with generalized bone pain, especially in the left ankle. He had been taking ADV for more than 1.5 years following a clinical breakthrough due to lamivudine-resistant HBV. Aggravating severe hypophosphatemia and elevated serum alkaline phosphatase levels with high bone fraction had been noted after 6 months of ADV therapy. Bone densitometry, simple bone X-rays, and a whole-body bone scan demonstrated osteoporosis and multiple areas with hot uptake, especially in the left ankle. All the image findings and symptoms improved after correcting the hypophosphatemia.