Risk of HBV transmission; lactic acidosis & severe hepatomegaly w/ steatosis; resistant HIV strains w/ possible cross-resistance to other antivirals. Should not be co-administered w/ tenofovir disoproxil fumarate. Caution in patients receiving medicinal products that may affect renal function or are excreted renally (eg, cyclosporin, tacrolimus, IV aminoglycosides, amphotericin B, foscarnet, pentamidine, vancomycin, cidofovir). Rare hereditary problems of galactose intolerance, Lapp lactase deficiency, or glucose-galactose malabsorption. Renal impairment. Not recommended in patients w/ CrCl <30 mL/min or on dialysis. Patients w/ advanced liver disease or cirrhosis may be at a higher risk for hepatic decompensation following hepatitis exacerbation. Women of childbearing potential not using contraception. Pregnancy & lactation. Elderly >65 yr. Childn <18 yr.