Used to treat chronic hepatitis B virus (HBV) infection in adults with evidence of active viral replication and liver damage. It works by inhibiting the reverse transcriptase enzyme of HBV, reducing viral load and slowing disease progression. Typically prescribed when other treatments are not suitable or have failed. Requires regular monitoring of kidney function due to potential nephrotoxicity. Not recommended for use in HIV-HBV coinfected patients without antiretroviral therapy due to risk of developing HIV resistance.