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Other Names: 3TC, Epivir®
Manufacturer: GlaxoSmithkline

What is it?

Lamivudine is an antiretroviral drug, specifically a nucleoside reverse transcriptase inhibitor. It is used to treat HIV, a retrovirus. Retroviruses use the genetic material in the body’s cells to produce more virus which can infect other cells.

How does it work?

Lamivudine interferes with the life cycle of HIV to stop it from producing more virus. Specifically, it ties up the reverse transcriptase enzyme so it cannot build the genetic material needed to make more virus and infect more cells.

How do I take it?

  • Lamivudine is available as 150mg and 300mg tablets.
  • The usual dose of Lamivudine is 1 tablet (150mg) twice daily OR 1 tablet (300mg) once daily.
  • Your dose may vary depending upon the study in which you are enrolled.
  • Lamivudine may be taken with or without food.

It is extremely important that you take lamivudine and your other antiretroviral medications exactly as directed. You should set up a system that will help you remember to take your medicines so that you do not miss any doses. If you miss a dose, take it as soon as possible; however, if you skip a dose, do not take two doses at once. Do not stop taking the medication for any reason at any time unless you are directed to do so by your study clinician. If you are unable to continue taking your medication due to side effects, you should contact your study clinician immediately.

Special Considerations

  • Lamivudine should be stored at controlled room temperature in a dry place, out of the reach of children.
  • Please bring your medication bottles (empty and partially used) to each study visit.


Some drugs taken together may have interactions that cause illness or impair the effectiveness of the drugs. It is a good idea to always check with your study clinician before taking any other medications, prescription or otherwise, to be sure it will not interact with lamivudine.

Side Effects

Not everyone experiences side effects. When they do occur, they may be mild, moderate or severe. Some side effects cannot be felt by the patient but can be found through laboratory tests, so it is important to see your study clinician regularly for checkups so that adverse effects can be detected early and treated.

The most common side effects of lamivudine are headache, fever, chills, muscle aches, dizziness, nausea, vomiting, insomnia, restlessness, and rash. Other side effects of lamivudine include changes in liver function, changes in pancreas function, neutropenia (decrease in white blood cells) and anemia (decrease in red blood cells).

Symptoms of anemia or neutropenia that you may notice include unusual tiredness or weakness, shortness of breath, or any sign of infection. If you begin having these symptoms, please contact your study clinician.

Nucleoside reverse transcriptase inhibitors such as zidovudine have been associated with a condition called lactic acidosis. Lactic acidosis is a build-up of lactic acid, a byproduct of muscle metabolism, in the blood. Early symptoms can be vague and non-specific and can include nausea, vomiting, fatigue, abdominal pain, sudden unexplained weight loss, and shortness of breath. If you are experiencing these symptoms and they cannot be explained by other causes, please contact your provider immediately. Although lactic acidosis is a rare condition, it can be life-threatening if not treated.

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