Pregnancy; elderly; child; renal or hepatic impairment. HIV antibody testing to be performed before initiation due to possible resistance development in untreated HIV infection. Increased risk of hepatotoxicity in females, obese patients and with prolonged treatment. Monitor renal function every 3 mth; hepatitis B biochemical, viral and serological markers every 6 mth and LFTs. Discontinue therapy if liver function worsens, severe hepatomegaly, steatosis or unexplained metabolic or lactic acidosis. Monitor hepatic function for several mth in patients whose antihepatitis therapy is discontinued as acute exacerbations of hepatitis may occur. Lactation: Unknown if excreted in breast milk.