Lamivudine is an antiviral medicine that prevents human immunodeficiency virus (HIV) or hepatitis B virus from multiplying in your body.

Epivir is for treating HIV in adults and children at least 3 months old. HIV is the virus that can cause acquired immunodeficiency syndrome (AIDS). Epivir is not a cure for HIV or AIDS.

Epivir-HBV is for treating hepatitis B in adults and children at least 2 years old. Epivir-HBV should not be used in people who are infected with both hepatitis B and HIV.

Lamivudine may also be used for purposes not listed in this medication guide.

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

You should not take Epivir-HBV (for treating hepatitis B) if you also take other medicine that contains lamivudine or emtricitabine, which includes Atripla, Biktarvy, Cimduo, Combivir, Complera, Descovy, Emtriva, Epzicom, Genvoya, Odefsey, Stribild, Symfi, Triumeq, Trizivir, and Truvada.

Tell your doctor if you have ever had:

• liver disease (especially hepatitis B or C, or a liver transplant);
• pancreatitis;
• kidney disease; or
• diabetes (liquid lamivudine contains 3 to 4 grams of sucrose per dose).

You may develop lactic acidosis, a dangerous build-up of lactic acid in your blood. This may be more likely if you have other medical conditions, if you've taken HIV medication for a long time, or if you are a woman. Ask your doctor about your risk.

Tell your doctor if you are pregnant, and use your medications properly to control your infection. HIV can be passed to your baby if the virus is not controlled during pregnancy. Your name may be listed on a registry to track any effects of antiviral medicine on the baby.

You should not breastfeed while you are using lamivudine to treat hepatitis B. Women with HIV or AIDS should not breast feed a baby. Even if your baby is born without HIV, the virus may be passed to the baby in your breast milk.

Use Epivir HBV (Oral) exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.

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

Mild symptoms of lactic acidosis may worsen over time, and this condition can be fatal. Get emergency medical help if you have: unusual muscle pain, trouble breathing, stomach pain, vomiting, irregular heart rate, dizziness, feeling cold, or feeling very weak or tired.

Call your doctor at once if you have:

• pancreas problems--severe pain in your upper stomach spreading to your back, nausea and vomiting, fast heart rate; or
• liver problems--swelling around your midsection, right-sided upper stomach pain, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).

Lamivudine affects your immune system, which may cause certain side effects (even weeks or months after you've taken this medicine). Tell your doctor if you have:

• signs of a new infection--fever, night sweats, swollen glands, cold sores, cough, wheezing, diarrhea, weight loss;
• trouble speaking or swallowing, problems with balance or eye movement, weakness or prickly feeling; or
• swelling in your neck or throat (enlarged thyroid), menstrual changes, impotence.

Common side effects may include:

• nausea, diarrhea;
• headache;
• fever, tiredness, general ill feeling;
• ear infection--ear pain or full feeling, trouble hearing, drainage from the ear, fussiness in a child; or
• nose or throat infection--stuffy nose, sneezing, sore throat, cough.

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.

Avoid taking other medications that contain an ingredient called sorbitol, often used as a sweetener in liquid medicines. Ask your pharmacist if you are not sure a medicine contains this ingredient.

Using lamivudine will not prevent your disease from spreading. Do not have unprotected sex or share razors or toothbrushes. Talk with your doctor about safe ways to prevent HIV transmission during sex. Sharing drug or medicine needles is never safe, even for a healthy person.