Tabulated List of Adverse Reactions: Adverse reactions considered at least possibly related to treatment with entecavir are listed by body system organ class. Frequency is defined as very common, common, uncommon, rare. Within each frequency grouping, undesirable effects are presented in order of decreasing seriousness. (See Table 2.)

Cases of lactic acidosis have been reported, often in association with hepatic decompensation, other serious medical conditions or drug exposures (see Precautions).
Treatment beyond 48 weeks: Continued treatment with entecavir for a median duration of 96 weeks did not reveal any new safety signals.