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Lamivudine is used to treat certain people with HIV. Some common side effects include headache, nausea, diarrhea, cough, sore throat, common cold symptoms, fever, or feeling unwell, tired, or like you don’t have your usual energy. Serious side effects are less common, but they may include liver problems, a buildup of lactic acid in your blood, inflammation of your pancreas, or immune problems. Missing doses of lamivudine or any of your medicines for HIV may lead to an increase in the amount of virus in your blood or make your infection harder to treat. Take your medicine exactly as recommended by your health care provider. Do not stop taking lamivudine without talking to your health care provider.

Uses

What is lamivudine used for?

Lamivudine is commonly used with other medicines to treat certain people with HIV.

Lamivudine may not be the right medicine for some HIV infections, depending on the virus causing the infection. Viruses in some locations may have developed resistance to lamivudine, which will make it not work as well.

Lamivudine may also be used for other conditions as determined by your health care provider.

Lamivudine can also be used to treat hepatitis B. See Lamivudine (Epivir-HBV) for more information.

How does lamivudine work (mechanism of action)?

Lamivudine is an antiretroviral that blocks an enzyme that HIV needs to make copies of itself. This helps to lower the levels of HIV in your body to fight the infection. Also, a lower amount of HIV in your body helps protect and preserve your immune system.

How is lamivudine supplied (dosage forms)?

Brands and other names

  • Epivir

Dosage forms and strengths

  • 150 mg and 300 mg oral tablets
  • 10 mg/mL oral solution

How should I store lamivudine?

Lamivudine should be stored at room temperature, between 68 F and 77 F (20 C and 25 C). It can be exposed to temperatures between 59 F and 86 F (15 C and 30 C) for shorter periods of time, such as when transporting it. Store in a cool, dry place. Store lamivudine liquid with the lid tightly closed when you are not using it. 

Side Effects

What are the most common side effects of lamivudine?

The most common side effects of lamivudine are listed below. These side effects may vary depending on the condition that is being treated or the age of the person taking it. Tell your health care provider if you have any of these side effects that bother you.

  • Headache
  • Nausea or diarrhea
  • A general feeling of being unwell or tired or not having your usual energy
  • Sore throat, common cold symptoms, or an infection in the ear, nose, or throat 
  • Cough
  • Fever 

There may be other side effects of lamivudine that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of lamivudine?

While less common, the most serious side effects of lamivudine are described below, along with what to do if they happen.

Severe Allergic Reactions. Lamivudine may cause allergic reactions, which can be serious. Stop taking lamivudine and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching or skin rash
  • Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Lactic Acidosis. Lamivudine may cause lactic acidosis (a buildup of lactic acid in your blood), which can be serious. Females and people who are overweight may be at a higher risk for liver problems. Stop taking lamivudine and get help right away if you have any of the following symptoms of lactic acidosis.

  • General ill feeling
  • Muscle pain
  • Trouble breathing
  • Drowsiness or dizziness
  • Stomach pain, nausea, or vomiting
  • Feel cold, especially in your arms and legs
  • Fast or irregular heartbeat

Liver Problems. Liver problems, including a big or fatty liver, can happen when taking lamivudine. In some cases, these liver problems can lead to death. Females and people who are overweight may be at a higher risk for liver problems. Call your health care provider right away if you have any of the following symptoms of liver problems.

  • Nausea or vomiting
  • Stomach or belly pain, especially on your right side
  • Fever
  • Weakness or unusual tiredness
  • Feeling dizzy or lightheaded
  • Itching
  • Loss of appetite
  • Light-colored poop
  • Dark-colored urine (pee)
  • Your skin or the whites of your eyes turning yellowish in color (also called jaundice)

Inflammation of the Pancreas (Pancreatitis). Lamivudine may cause inflammation of the pancreas, which is called pancreatitis. Stop taking lamivudine and call your health care provider right away if you have symptoms of pancreatitis, including vomiting or severe pain in the upper part of your belly that travels to your back.

Immune System Changes. When you start lamivudine, your immune system might get stronger and start fighting infections that have been hiding inside your body for a long time. The type of symptoms you may have will depend on the infection. Tell your health care provider right away if you notice any of the following new symptoms of infection. 

  • Fever, sweats, chills, or muscle aches
  • Swollen lymph nodes
  • Vision problems
  • Confusion, problems talking, or headache
  • Skin problems, such as a painful rash or warts
  • Cough or coughing up blood
  • Weakness or coordination problems 

Warnings & Precautions

Who should not use lamivudine?

Allergies to Ingredients. People who are allergic to any of the following should not take lamivudine.

  • Epivir
  • Lamivudine
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific lamivudine products they stock.

What should I know about lamivudine before using it?

Do not take lamivudine unless it has been prescribed to you by a health care provider. Take it as prescribed.

It is important to take your lamivudine as it is prescribed by your health care provider. Missing doses may lead to an increase in the amount of virus in your blood or make your infection harder to treat. Taking it as prescribed can reduce the risk that your infection becomes resistant to lamivudine or other similar medicines. Do not stop taking lamivudine without talking to your health care provider. 

Do not share lamivudine with other people, even if they have the same condition as you. It may harm them.

Keep lamivudine out of the reach of children.

A liquid form of lamivudine is available if you have trouble swallowing tablets. Use an accurate measuring device to measure your dose of liquid lamivudine. A household spoon is not an accurate measuring device and may cause you to take the wrong dose. Ask your pharmacist what measuring device to use.

The dose of lamivudine for children is based on body weight. Tell your child’s health care provider if your child’s weight changes. Some weight changes may mean your child needs a different dose to make sure the medicine continues to work. Talk to your health care provider if you have any concerns.

Taking lamivudine to treat HIV does not keep you from being able to pass the infection to someone else. Follow your health care provider’s recommendations to reduce your risk of giving HIV to someone else. These may include things like using condoms correctly every time you have sex or not sharing needles or syringes. Talk to your health care provider if you have questions. 

What should I tell my health care provider before using lamivudine?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if lamivudine is right for you.

In particular, make sure that you discuss any of the following.

Hepatitis B Infection. If you have HIV and hepatitis B, stopping lamivudine can cause a serious flare-up or worsening of your hepatitis B. Your health care provider will test you for hepatitis B before or when starting this medicine. Do not run out of lamivudine or stop taking it without talking to your health care provider first. If you have HIV and hepatitis B and stop taking lamivudine, keep all appointments for blood tests so that your health care provider can check the health of your liver. 

Current and Past Health Conditions. Tell your health care provider if you have any of the following.

  • Kidney problems
  • Diabetes (lamivudine liquid has sucrose, which is a type of sugar)
  • Liver problems, including hepatitis B or C

Other Medicines and Supplements. Lamivudine may interact with other medicines and supplements. Before taking lamivudine, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how lamivudine could affect pregnancy or harm a fetus. Tell your health care provider if you are pregnant or plan to become pregnant. Your health care provider will let you know if you should take lamivudine while you are pregnant or trying to get pregnant.

If you become pregnant while taking lamivudine, talk to your health care provider about registering for the Antiretroviral Pregnancy Registry. Your health care provider can register you by calling 800-258-4263. This registry collects safety information about the use of antiretroviral medicines during pregnancy.

Breastfeeding. Lamivudine passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will let you know if you should stop breastfeeding or stop lamivudine. 

Interactions

Does lamivudine interact with foods or drinks?

There are no known interactions between lamivudine and foods or drinks.

It is unknown if drinking alcohol will affect lamivudine, but heavy drinking can slow your immune response and make it harder for your body to fight infections.

Does lamivudine interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking lamivudine.

  • Sorbitol, which is a laxative used to help relieve constipation
  • Any medicine that has sorbitol in it (sorbitol is used as a sweetener for many liquid medicines)

This may not be a complete list of medicines that can interact with lamivudine. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much lamivudine?

If you or someone else has used too much lamivudine, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of lamivudine?

Missing doses of lamivudine can cause it to not work as well over time. So, it is important not to miss or skip doses.

If you miss a dose, take it as soon as you remember. Do not take double or extra doses.