Perform HIV or HBV Ab test prior to therapy. Immunosuppressed patients or those receiving immunosuppressive regimens, orthotrophic liver transplant patients & patients co-infected w/ HCV or hepatitis D virus. Lactic acidosis or severe hepatomegaly w/ steatosis; known risk factors for liver disease. Avoid concurrent or recent use of nephrotoxic agent. Not recommended w/ co-administration of didanosine. Not to be used in combination w/ emtricitabine/tenofovir- or efavirenz/emtricitabine/tenofovir-containing prep. May affect ability to drive & use machines. Renal impairment including acute renal failure & Fanconi syndrome. Women of childbearing potential must use effective contraception. Pregnancy. Not to be used during lactation. Childn <12 yr. Elderly >65 yr.