It is very important that your doctor check your progress at regular visits. This will allow your doctor to see if the medicine is working properly. Blood tests may be needed to check for unwanted effects.
It is important to tell your doctor if you become pregnant. Your doctor may want you to join a pregnancy registry for patients taking this medicine.
If you have or get HIV (human immunodeficiency virus) infection, be sure to discuss your treatment with your doctor. If you are taking this medicine to treat chronic hepatitis B and are not taking medicines for your HIV at the same time, some HIV treatments that you take in the future may be less likely to work. Your doctor may need you to get an HIV test before you start taking this medicine and anytime after that when there is a chance you were exposed to HIV. This medicine will not help your HIV infection.
Two rare but serious reactions to this medicine are lactic acidosis (too much acid in the blood) and liver toxicity, which includes an enlarged liver. These are more common if you are female, very overweight (obese), or have been taking anti-HIV medicines for a long time. Call your doctor right away if you or your child feel tired, weak, dizzy, or nauseated, if you vomit or have stomach pain, dark urine, light-colored stools, unusual muscle pains, or trouble with breathing, or if your skin or eyes turn yellow.
Liver disease may become worse if treatment with entecavir is stopped. Do not stop taking entecavir unless your doctor tells you to stop.
Treatment with entecavir has not been shown to decrease the chance of giving hepatitis B virus infection to other people through sexual contact or blood contamination.