Used primarily in the treatment of chronic hepatitis B virus (HBV) infection. It works by inhibiting the viral DNA polymerase enzyme, thereby suppressing viral replication. Adefovir dipivoxil, the prodrug form, is orally administered and converted in the body to the active form, adefovir. It is especially useful in patients who have developed resistance to other antiviral agents like lamivudine. Due to potential kidney toxicity, renal function must be monitored during long-term therapy. Not typically used as a first-line treatment due to the availability of safer alternatives with higher potency and lower resistance rates.