Besifovir is primarily used as an antiviral medication for the treatment of chronic hepatitis B virus (HBV) infection. It works by inhibiting the replication of the virus, thereby reducing the viral load in the body. The drug is particularly effective in patients who have developed resistance to other antiviral therapies. It is administered orally, making it convenient for long-term treatment regimens. Besifovir is also noted for its favorable safety profile, with fewer side effects compared to some other HBV treatments. Its ability to maintain sustained virological response makes it a valuable option in managing chronic hepatitis B and preventing complications such as liver cirrhosis and hepatocellular carcinoma.