You Should Not Take Entecavir If You Are Allergic To It, Or If You Also Have Hiv (Human Immunodeficiency Virus) That Is Not Being Treated.
You May Need To Be Tested For Hiv Before You Start Taking Entecavir. Taking Medicine To Treat Chronic Hepatitis B Can Cause Hiv Infection To Become Resistant To Certain Hiv And Aids Medications.
Tell Your Doctor If You Have Ever Had:
Hiv Or Aids (Or If You Have Been Exposed To Hiv);
Kidney Disease;
Liver Problems Other Than Hbv;
A Liver Transplant; Or
If You Also Take Lamivudine (Epivir, Epzicom, Trizivir) Or Telbivudine (Tyzeka).
Tell Your Doctor About All Medicines You Have Used To Treat Hepatitis B In The Past. Entecavir May Not Be The Right Medication If You Have Used Certain Other Medicines For Hbv.
You May Develop Lactic Acidosis, A Dangerous Build-up Of Lactic Acid In Your Blood. This May Be More Likely If You Are Overweight, If You've Taken Antiviral Medication For A Long Time, Or If You Are A Woman. Ask Your Doctor About Your Risk.
Tell Your Doctor If You Are Pregnant Or Breastfeeding.
If You Are Pregnant, Your Name May Be Listed On A Pregnancy Registry To Track The Effects Of Entecavir On The Baby.

Take The Medicine As Soon As You Can, But Skip The Missed Dose If It Is Almost Time For Your Next Dose. Do Not Take Two Doses At One Time.
Get Your Prescription Refilled Before You Run Out Of Medicine Completely.

Get Emergency Medical Help If You Have Signs Of An Allergic Reaction: Hives; Difficult Breathing; Swelling Of Your Face, Lips, Tongue, Or Throat.
Some People Using Entecavir Develop Lactic Acidosis, Which Can Be Fatal. Get Emergency Medical Help If You Have Even Mild Symptoms Such As:
Unusual Muscle Pain;
Feeling Cold;
Trouble Breathing;
Feeling Dizzy, Light-headed, Tired, Or Very Weak;
Stomach Pain, Vomiting; Or
Fast Or Irregular Heartbeats.
Entecavir May Also Cause Severe Liver Symptoms. Call Your Doctor At Once If You Have: Swelling Around Your Midsection, Nausea, Stomach Pain, Loss Of Appetite, Dark Urine, Clay-colored Stools, Jaundice (Yellowing Of The Skin Or Eyes).

Reactivation Of Hepatitis B Refers To The Abrupt Increase In Hepatitis B Virus (Hbv) Replication In A Patient With Inactive Or Resolved Hepatitis B. Reactivation Can Occur Spontaneously, But More Typically Is Triggered By Immunosuppressive Therapy Of Cancer, Autoimmune Disease, Or Organ Transplantation.