Entecavir, sold under the brand name Baraclude, is an antiviral medication used in the treatment of hepatitis B virus infection.

[6] Common side effects include headache, nausea, high blood sugar, and decreased kidney function.

[3] Less common effects include trouble sleeping and gastrointestinal symptoms such as sour stomach, diarrhea, and vomiting.

Other nucleoside and nucleotide analogues include lamivudine, telbivudine, adefovir dipivoxil, and tenofovir.

Entecavir is recommended on an empty stomach at least 2 hours before or after a meal, generally at the same time every day.

[3] Bristol-Myers Squibb was the original patent holder for Baraclude, the brand name of entecavir in the US and Canada.

The lawsuit resulted in a relatively rare in the pharmaceutical field patent invalidation for obviousness, which was affirmed in June 2014, by the US Court of Appeals for the Federal Circuit (752 F.32d 967).