Entecavir

Entecavir is an antiviral medicine that treats chronic hepatitis B virus (HBV) in adults and children who are at least 2 years old and weigh at least 22 pounds (10 kilograms).

Entecavir may also be used for reasons not mentioned in this medication guide.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Take the medicine exactly as directed.

Take entecavir on an empty stomach, at least 2 hours after a meal and 2 hours before the next meal.

Measure liquid medicine with the supplied measuring device (not a kitchen spoon).

Doses are based on weight in children and teenagers. Your child's dose may change if the child gains or loses weight.

Use entecavir regularly to get the most benefit and to keep your condition from getting worse. Call your doctor if your hepatitis symptoms do not improve, or if they get worse.

Do not change your dose or dosing schedule without your doctor's advice. Every person with HBV should remain under the care of a doctor.

If you've had hepatitis B, it may come back or get worse after you stop taking entecavir. You may need frequent liver function tests for several months.

Store tightly closed at room temperature, away from moisture, heat, and light.

Keep liquid medicine in its original carton. Throw away any unused medicine after the expiration date on the label has passed.

You may not take entecavir if you have untreated HIV (human immunodeficiency virus). Ask your doctor about your individual risk.

You may develop lactic acidosis, which is a dangerous build-up of lactic acid in your blood. Call your doctor or get emergency medical help if you have unusual muscle pain, trouble breathing, stomach pain, dizziness, feeling cold, or feeling very weak or tired.

This medication can cause liver problems. Call your doctor if you have swelling around your midsection, pain in the upper right side of your stomach, loss of appetite, dark urine, clay-colored stools, or jaundice (yellowing of the skin or eyes).

If you've had hepatitis B, it may come back or get worse after you stop taking entecavir. You may need frequent liver function tests for several months.

You should not take entecavir if you are allergic to it.

You may need to be tested for HIV before you start taking entecavir. Taking medicine for chronic hepatitis B can cause HIV infection to resist certain HIV and AIDS medications.

Tell your doctor if you have or have ever had:

• HIV or AIDS (or if you have been exposed to HIV);
• if you also take lamivudine (Epivir, Epzicom, Trizivir) or telbivudine (Tyzeka);
• liver problems other than HBV;
• a liver transplant; or
• kidney disease.

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 to treat HBV.

You may develop lactic acidosis, a serious build-up of lactic acid in your blood. This may be more likely if you are overweight, if you have 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 monitor the effects of entecavir on the baby.

Get emergency medical help if you have signs of an allergic reaction: hives, difficulty breathing, swelling of your face, lips, tongue, or throat.

Some people taking entecavir develop lactic acidosis. Get emergency medical help if you have symptoms of lactic acidosis 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 right away 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).

Common side effects of entecavir may include:

• nausea;
• dizziness, feeling tired; or
• headache.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1 800 FDA 1088.

Take the medicine as soon as you remember, but skip the missed dose if it is nearly time for your next dose. Do not take two doses at the same time.

Get your prescription refilled before you completely run out of medicine.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Using entecavir will not stop your disease from spreading. Follow your doctor's instructions on how to prevent passing the disease to someone else.

Other drugs may affect entecavir, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all other medicines you are using.