Use associated with decreases in bone mineral density and osteomalacia. May cause fat redistribution. Patients may develop immune reconstitution syndrome resulting in occurrence of inflammatory response to indolent or residual opportunistic infection. Lactic acidosis and severe hepatomegaly with steatosis reported with tenofovir and other nucleoside analogs, including fatal cases. Use with caution in risk factors for liver disease (risk may be increased with female gender, obesity, pregnancy or prolonged exposure). May cause renal toxicity (acute renal failure and/or Fanconi syndrome). Avoid use with concurrent or recent nephrotoxic therapy. Use with caution in low body weight, or concurrent medications which increase tenofovir levels. Severe, acute exacerbation of hepatitis B may occur upon discontinuation. Treatment of HBV in unrecognized/untreated HIV may lead to HIV resistance. Use with caution in hepatic impairment. Do not use as monotherapy in treatment of HIV. Treatment of HIV in patients with unrecognized/untreated HBV may lead to rapid HBV resistance. Use with caution in renal impairment (CrCl <50 mL/minute). Do not use concurrently with adefovir for treatment of chronic hepatitis B. Use with caution in patients taking strong CYP3A4 inhibitors, moderate or strong CYP3A4 inducers and major CYP3A4 substrates. Do not use concurrently with tenofovir combination products.