[{"from": "human", "value": "Provide a brief overview of this molecule. [C][=C][C@H1][Branch1][O][C][C@@H1][Branch1][=Branch1][C@H1][Ring1][Branch1][C][O][O][N][C][=N][C][=C][Ring1][Branch1][N][=C][Branch1][=Branch1][N][C][Ring1][=Branch1][=O][N]"}, {"from": "gpt", "value": "The molecule is an oral antiviral drug used in the treatment of hepatitis B infection. It is marketed under the trade name Baraclude (BMS).  Entecavir is a guanine analogue that inhibits all three steps in the viral replication process, and the manufacturer claims that it is more efficacious than previous agents used to treat hepatitis B (lamivudine and adefovir). It was approved by the U.S. Food and Drug Administration (FDA) in March 2005."}]