Combivir (Lamivudine and Zidovudine) - Oral

Warning:

The United States Food and Drug Administration (FDA) has issued a boxed warning for Combivir (lamivudine and zidovudine). Boxed warnings are the agency’s strongest warnings for serious and potentially life-threatening risks.

The boxed warning:

Zidovudine is linked to abnormal blood cell counts, such as low neutrophils or severe anemia. Long-term use of zidovudine is also connected to muscle weakness, stiffness, and cramps. There are also reports of high lactic acid levels in the body, serious hepatomegaly (enlarged liver), and fatty liver disease with Combivir. Some people may also experience worsening hepatitis B infections after stopping lamivudine.

What Is Combivir?

Combivir (lamivudine and zidovudine) is an orally administered combination drug used to treat human immunodeficiency virus 1 (HIV-1) in people weighing at least 66 pounds.

While the combination of lamivudine and zidovudine does not cure HIV, it may lessen your chance of developing acquired immunodeficiency syndrome (AIDS) and HIV-related illnesses such as infections or cancer.

Combivir is a combination medication that contains two nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs). NRTIs are used in tandem with other antiretrovirals (ARVs).

In general, NRTIs work by inserting themselves into the HIV DNA, making it useless. So, HIV can't make more copies of itself.

While the primary ingredient found in Combivir, the combination of lamivudine and zidovudine, is available as a combinational single generic product (oral tablets), branded Combivir itself is available as a prescription tablet to be consumed by mouth.

Drug Facts

Generic Name: Lamivudine and zidovudine

Brand Name(s): Combivir

Drug Availability: Prescription

Therapeutic Classification: Antiretroviral agent

Available Generically: Yes

Controlled Substance: N/A

Administration Route: Oral

Active Ingredient: Lamivudine and zidovudine

Dosage Form(s): Tablet

What Is Combivir Used For?

The FDA has approved Combivir as a medication option to treat HIV-1. It's typically used in combination with ARV medications for people who weigh 66 pounds or more.

Combivir is classified as an NRTI, which belongs to a class of medications known as antiviral agents. NRTIs are primarily used to treat HIV, while some also are approved to treat chronic hepatitis B (a serious infection of the liver).

HIV affects roughly 1.2 million people in the United States (U.S.)—with more than 10% unaware of their HIV status.

In a comparison of the two, HIV-1 is the more deadly type of HIV that makes up 95% of all infections. Meanwhile, HIV-2 is less infectious and is mainly found in West Africa and its surrounding countries. HIV-2 is less fatal and progresses slower than HIV-1.

During the first few weeks of an HIV infection, you'll likely have only flu-like symptoms. Without treatment, HIV can cause the development of AIDS over time.

AIDS is the late stage of an HIV infection. This is when your immune system (body's defense system) is so weak that you may have trouble fighting off infections.

How to Take Combivir

Combivir is taken with other antiretroviral medications. In general, this medication is taken by mouth twice daily with or without food. Take Combivir at around the same times every day.

Follow the directions on your prescription label carefully and ask your healthcare provider to explain any part you do not understand. Take this medication exactly as directed. Do not take more or less of it or take it more often than prescribed by your healthcare provider.

Combivir controls HIV infection but does not cure it. Continue to take it even if you feel well.

Storage

When you receive Combivir from the pharmacy, keep the medication at room temperature between 68 to 77 degrees F.

Keep your medications tightly closed and out of the reach of children and pets, ideally locked in a cabinet or closet. Do not store your medication in the bathroom.

Try to avoid pouring unused and expired drugs down the drain or in the toilet. Visit the FDA's website to know where and how to discard all unused and expired drugs. You can also find disposal boxes in your area. Ask your pharmacist or healthcare provider if you have any questions about the best ways to dispose of your medications.

If you plan to travel with Combivir, get familiar with your final destination's regulations. Checking with the U.S. embassy or consulate might be a helpful resource. In general, however, make a copy of your Combivir prescription. It's also a good idea to keep your medication in its original container from your pharmacy with your name on the label.

If you have any questions about traveling with your medicine, be sure to ask your pharmacist or healthcare provider.

How Long Does Combivir Take to Work?

After taking Combivir in combination with ARV medications for 12 months, your HIV may stop worsening.

What Are the Side Effects of Combivir?

This is not a complete list of side effects, and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or a healthcare provider. You may report side effects to the FDA at fda.gov/medwatch or 800-FDA-1088.

Common Side Effects

Common side effects with Combivir may include:

Severe Side Effects

The FDA has issued a boxed warning for Combivir. Boxed warnings are the agency’s strongest warnings for serious and potentially life-threatening risks.

The boxed warning:

Zidovudine is linked to abnormal blood cell counts, such as low neutrophils or severe anemia. Long-term use of zidovudine is also connected to muscle weakness, stiffness, and cramps.

There are also reports of high lactic acid levels in the body, serious hepatomegaly, and fatty liver disease with Combivir. Some people may also experience worsening hepatitis B infections after stopping lamivudine.

Get medical help if you develop the following serious side effects with Combivir:

  • Severe allergic reaction: If you have a severe allergic reaction to Combivir, symptoms may include itchiness, swelling, and breathing difficulties.
  • Abnormal blood cell count: The zidovudine medication in the Combivir tablet is linked to abnormal blood cell counts—specifically neutrophils (a type of white blood cell). Low white blood cells (WBCs) might raise the likelihood of infections. For this reason, be on the lookout for symptoms of an infection. Zidovudine is also connected to severe anemia. Symptoms of anemia may include excessive tiredness and pale-looking skin.
  • Abnormal fat changes: Combivir is linked to abnormal fat changes or distribution. Fat might build up in certain parts of the body and thin out in others.
  • Immune reconstitution syndrome (IRS): When you take Combivir, your immune system may become stronger again. As your immune system gains strength, however, it might start fighting infections that have been hiding in your body. So, keep an eye out for symptoms of an infection. The immune system may also become overreactive and attack parts of your body by mistake. General symptoms of these autoimmune diseases may include rash, low energy, joint pain, and concentration difficulties
  • Lactic acidosis: Lactic acidosis is a condition of high lactic acid levels in your body. Symptoms may include weakness, nausea, and vomiting. Lactic acidosis can become a serious situation.
  • Liver problems: It's possible to develop liver toxicity with Combivir. Examples of some liver problems may include enlarged liver and fatty liver disease. If you're experiencing worsening liver function, symptoms may include upper right-sided stomach pain, dark urine, and jaundice (yellowing of your eyes or skin).
  • Myopathy: Long-term use of Combivir may result in myopathy. Symptoms of myopathy may include muscle weakness, stiffness, and cramps.
  • Pancreatitis: Combivir might raise your risk of pancreatitis, an inflammation (swelling) of the pancreas. The pancreas secretes certain enzymes (proteins) that help with digestion. Symptoms of pancreatitis may include stomach tenderness, fast heart rate, and fever.
  • Worsening hepatitis B infection: After stopping lamivudine, some people experienced worsening hepatitis B (a serious liver infection preventable by vaccination). There are also reports of hepatitis B virus that become resistant to lamivudine. Worsening hepatitis B infection may have some similar symptoms to worsening liver function.

Call 911 if your symptoms feel life-threatening.

Long-Term Side Effects

Long-term side effects of Combivir are very similar to its severe side effects, which may include:

  • Abnormal fat changes: Combivir is linked to abnormal fat changes or distribution. Fat might build up in certain parts of the body and thin out in others. After switching to another antiretroviral therapy (ART) that doesn't contain zidovudine, the side effect might be partly reversible. This, however, may take months or years.
  • Immune reconstitution syndrome (IRS): Combivir may cause an overreactive immune system that causes an autoimmune disease.
  • Myopathy: Long-term use of Combivir might result in muscle weakness, cramps, and stiffness.
  • Worsening hepatitis B infection: After stopping lamivudine, some people experience worsening hepatitis B infections. There are also reports of hepatitis B becoming resistant to lamivudine.

Report Side Effects

Combivir may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Combivir Should I Take?


Drug Content Provided and Reviewed by IBM Micromedex®

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (tablets):
    • For human immunodeficiency virus (HIV) infection:
      • Adults and children who weigh at least 30 kilograms (kg)—One tablet two times a day.
      • Children who weigh less than 30 kg—Use is not recommended.

Modifications

The following modifications (changes) should be kept in mind when using Combivir:

Severe allergic reaction: Avoid using Combivir if you have a known allergy to it or any of its ingredients. Ask your pharmacist or healthcare provider for a complete list of the ingredients if you're unsure.

Dose-limiting side effects: Some people may need lower doses of Combivir because they experience intolerable side effects with Combivir. If this is the case, Combivir isn't a viable option. The lamivudine and zidovudine medications, however, are separately available at lower doses in tablet and liquid dosage forms.

Pregnancy: Lamivudine was found to have negative effects on the fetus of rabbits—but not in rats. In some rabbit and rat studies, zidovudine was linked to negative effects on the unborn fetus. However, based on available information in humans, lamivudine or zidovudine don't appear to have negative effects on the unborn fetus.

Discuss with your healthcare provider if you plan to become pregnant or are pregnant. Your healthcare provider can help you weigh the benefits and risks of Combivir during your pregnancy. They can also help you enroll in the APR by calling 1-800-258-4263.

Breastfeeding: Lamivudine and zidovudine are present in breast milk, and very small amounts reach the bloodstream of nursing infants. Negative effects seem minimal with lamivudine, but there are some reports of anemia with zidovudine in nursing babies.

In general, breastfeeding isn't recommended to limit the chances of HIV passing onto an HIV-negative baby. Avoiding breastfeeding may also prevent treatment-resistant HIV in HIV-positive babies.

Talk with your healthcare provider if you plan to breastfeed. Your healthcare provider will help you weigh the benefits and harms of Combivir while nursing. They can also discuss the different ways available to feed your baby.

Older adults over 65: Clinical studies haven't included a large enough number of people in this age group to see whether they respond differently from younger adults. However, older adults with several medical conditions or taking several medications should use caution. Older adults might be more sensitive to side effects from medications.

Children: The FDA approved Combivir for people weighing at least 66 pounds. If your child weighs less than 66 pounds, Combivir isn't a viable option. However, lamivudine and zidovudine medications are separately available at lower doses in tablet and liquid dosage forms.

Kidney or liver problems: Individuals with kidney or liver problems may not be able to clear the medication from their bodies as easily. This means the medicine stays in the body longer and can have increased side effects.

For this reason, you may need lower lamivudine and zidovudine doses depending on your kidney or liver function. If this is the case, Combivir isn't a viable option. As previously mentioned, lamivudine and zidovudine are separately available at lower doses in tablet and liquid dosage forms.

People assigned female at birth with a body mass index (BMI) over 30: These higher-BMI females might have a higher risk of experiencing certain side effects with Combivir. These side effects may include high lactic acid levels and liver problems, such as enlarged liver and fatty liver disease. Your healthcare provider may closely monitor you for these side effects.

Pancreatitis: Combivir may raise your risk of pancreatitis, which is inflammation (swelling) of your pancreas. The pancreas secretes certain enzymes (proteins) that help with digestion. Your healthcare provider may closely monitor you if you have a history of pancreatitis or risk factors for this condition.

Hepatitis C: While interferon-alpha and ribavirin are no longer initial go-to options for hepatitis C (a liver infection spread through contact by blood from an infected individual), you may see these medications in certain situations. If interferon-alpha is used with Combivir, your healthcare provider will closely monitor you for worsening liver function and anemia.

They may also check your blood cell counts to make sure you're not having low neutrophils. Ribavirin with Combivir, on the other hand, isn't typically recommended.

BMI

BMI is a dated, biased measure that doesn’t account for several factors, such as body composition, ethnicity, race, gender, and age. Despite being a flawed measure, BMI is widely used today in the medical community because it is an inexpensive and quick method for analyzing potential health status and outcomes.

Missed Dose

If you accidentally forgot your Combivir dose, take it as soon as you remember. If it's already close to your next scheduled dose, then skip the missed dose and take the following dose at your next scheduled dosing time. Don't try to double up to make up for the missed dose.

Try to find ways that work for you to help yourself remember to routinely keep your appointments and take your medication. If you miss too many doses, Combivir might be less effective and result in treatment-resistant HIV.

Overdose: What Happens If I Take Too Much Combivir?

There is limited information available about Combivir overdoses. Symptoms of a suspected overdose, however, may include:

If you think that you're experiencing an overdose or life-threatening symptoms, seek immediate medical attention.

What Happens If I Overdose on Combivir?

If you think you or someone else may have overdosed on Combivir, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Combivir, call 911 immediately.

Precautions

Drug Content Provided and Reviewed by IBM Micromedex®

It is very important that your doctor check the progress of you or your child at regular visits to make sure that this medicine is working properly. Blood tests may be needed to check for unwanted effects.

Do not take any other medicine containing emtricitabine, lamivudine, or zidovudine (eg, Atripla®, Complera®, Emtriva®, Epivir®, Epzicom®, Retrovir®, Trizivir®, or Truvada®).

Do not take any other medicines without checking with your doctor first. To do so may increase the chance of side effects from lamivudine and zidovudine combination.

If you or your child have both HIV and hepatitis B virus (HBV) infections, liver disease can become worse when lamivudine and zidovudine treatment is stopped. Discuss any changes in your treatment and medicines with your doctor.

Zidovudine may cause some serious side effects, including blood or bone marrow problems. Symptoms of a blood or bone marrow problem include fever, chills, sore throat, pale skin, or unusual tiredness or weakness. These problems may require blood transfusion or temporarily stopping treatment with lamivudine and zidovudine combination. Check with your doctor if any new health problems or symptoms occur while you or your child are taking lamivudine and zidovudine combination.

Two rare but serious reactions to this medicine are lactic acidosis (too much acid in the blood) and liver toxicity. These are more common if you are female, very overweight (obese), or have been taking anti-HIV medicines for a long time. Call your doctor right away if you or your child have more than one of these symptoms: abdominal discomfort or cramping, dark urine, decreased appetite, diarrhea, general feeling of discomfort, light-colored stools, muscle cramping or pain, nausea, unusual tiredness or weakness, trouble breathing, vomiting, or yellow eyes or skin.

Tell your doctor if you or your child have severe muscle pain, tenderness, or weakness, especially if you take this medicine for a long time.

When you or your child start taking HIV medicines, your immune system may get stronger. If you have infections that are hidden in your body (eg, pneumonia or tuberculosis), you may notice new symptoms when your body tries to fight them. If this occurs, tell your doctor right away.

This medicine may cause a decrease or loss of body fat, especially in your face, arms, legs, or buttocks, when it is used for a long time. Talk to your doctor if you have concerns.

This medicine does not decrease the risk of transmitting the HIV infection to others through sexual contact or by contaminated blood. Make sure you understand and practice safe sex, even if your partner also has HIV. Avoid sharing needles with anyone.

What Are Reasons I Shouldn’t Take Combivir?

Before taking Combivir, talk with your healthcare provider if any of the following applies to you:

Severe allergic reaction: If you have a severe allergic reaction to Combivir or any of its components (ingredients), this medication isn't a viable option for you.

Dose-limiting side effects: Some people may need lower doses of lamivudine and zidovudine because they experience intolerable side effects with Combivir. If this is the case, Combivir isn't a viable option. The lamivudine and zidovudine medications, however, are separately available at lower doses in tablet and liquid dosage forms.

Pregnancy: Based on available information on humans, Combivir doesn't appear to have negative effects on the unborn fetus. Consider enrolling in the Antiretroviral Pregnancy Registry (APR). Your healthcare provider can enroll you by calling 1-800-258-4263. You can also talk with your healthcare provider to help you weigh the benefits and risks of Combivir during your pregnancy.

Breastfeeding: Lamivudine and zidovudine are present in breast milk, and very small amounts reach the bloodstream of nursing infants. Negative effects seem minimal with lamivudine, but there are some reports of anemia with zidovudine in nursing babies.

In general, breastfeeding isn't recommended to limit the chances of HIV passing onto an HIV-negative baby. Avoiding breastfeeding may also prevent treatment-resistant HIV in HIV-positive babies. Reach out to your healthcare provider to talk about the benefits and harms of Combivir while breastfeeding.

Older adults over 65: There isn't enough information to assess differences in response to Combivir between older and younger adults. In general, however, older adults should use caution.

Children: The FDA approved Combivir for people weighing at least 66 pounds. If your child weighs less than 66 pounds, Combivir isn't a viable option. The lamivudine and zidovudine medications, however, are separately available at lower doses in tablet and liquid dosage forms.

Kidney or liver problems: Individuals with kidney or liver problems may not be able to clear the medication from their bodies as easily. This means the medicine stays in the body longer and can have increased side effects.

Hepatitis C: While interferon-alpha and ribavirin are no longer initial go-to options for hepatitis C, you may see these medications in certain situations. If interferon-alpha is used with Combivir, your healthcare provider will closely monitor you for worsening liver function and anemia. They may also check your blood cell counts to make sure you're not having low neutrophils (a type of white blood cell). Ribavirin with Combivir, on the other hand, isn't typically recommended.

What Other Medications Interact With Combivir?

Avoid sorbitol (a type of sweetener) with the lamivudine medication in Combivir. Sorbitol may reduce lamivudine levels, lowering its effectiveness.

As for the zidovudine medication in Combivir, avoid medications that work against zidovudine. These medications might make zidovudine less effective. Examples of these medications may include ribavirin for hepatitis C and doxorubicin for various cancers—like breast cancer.

Zidovudine may also interact with medications that have the similar side effect of abnormal blood cell counts. Ribavirin and interferon-alpha for hepatitis C can do this. The ganciclovir antiviral is another example. Combining these medications with zidovudine may further worsen this side effect.

For more detailed information about medication interactions with Combivir, talk with your pharmacist or healthcare provider.

And be sure to talk with your healthcare provider about any other medicines you take or plan to take, including over-the-counter (OTC), nonprescription products, vitamins, herbs, or plant-based medicines.

What Medications Are Similar?

Combivir is a combination tablet that contains lamivudine and zidovudine. Both of these medications are NRTIs.

Other NRTIs may include:

Of all the NRTIs, experts don't generally recommend zidovudine-based therapies anymore. So, this means that Combivir isn't a typical go-to treatment option for HIV. You may, however, see an intravenous (IV; into the vein) infusion of zidovudine in some pregnant parents before delivery. This is to prevent HIV from passing to the newborn.

In general, zidovudine is no longer recommended as an initial treatment option because of its serious side effects. Compared to other antiretroviral therapies (ARTs), some zidovudine-based ones are also less effective.

While all of these medications are NRTIs, you may see several different ART options that contain two NRTIs.

Frequently Asked Questions

  • Where is Combivir available?

    Combivir is available as a prescription from your healthcare provider. Your local retail pharmacy may carry it. If your pharmacy doesn't have Combivir in stock, they might be able to order it for you.

  • How much does Combivir cost?

    Combivir is available as a generic combination tablet that contains two nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs): lamivudine and zidovudine. So, this might help save you on costs.

    If cost is a concern, there are other expert-preferred NRTIs. Work with your pharmacist and healthcare provider. They can help you determine if other NRTIs are viable options for you.

  • What do I do if I'm having abnormal fat changes?

    If you're experiencing abnormal fat changes, don't make any changes to your HIV medications.

    Instead, reach out to your healthcare provider. They will advise you on what to do. One potential option is a medication called Egrifta SV, which may help address abnormal fat changes from your HIV medications or HIV infection.

How Can I Stay Healthy While Taking Combivir?

If you're taking Combivir, chances are HIV is negatively affecting your quality of life. You may have tried different approaches or treatments. While living with HIV does have its challenges, there are ways to help improve your quality of life.

Refer below for some general tips to support your health:

  • Take HIV-related medications as recommended by your healthcare provider.
  • Keep up with labs and appointments with your healthcare provider.
  • Learn more about HIV.
  • Share with your loved ones about your HIV status when you are ready. While this is a difficult step, it's important to build your social support network.
  • Stop smoking. Smokers are more likely to have heart disease and cancer compared to the general public.
  • Routinely exercising lowers your heart disease risk and bone loss.
  • Practice safer sex to limit the spread of HIV.
  • Stay up to date with your vaccines.
  • Consider support groups or work with a mental healthcare professional to help you find coping strategies that change how you think, feel, react, or respond to living with HIV.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended as a replacement for medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

19 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Food and Drug Administration. Combivir (lamivudine and zidovudine) prescribing information.

  2. MedlinePlus. Lamivudine and zidovudine.

  3. HIV.gov HIV/AIDS glossary: nucleoside reverse transcriptase inhibitor (NRTI).

  4. HIV.gov. U.S. statistics.

  5. Nyamweya S, Hegedus A, Jaye A, Rowland-Jones S, Flanagan KL, Macallan DC. Comparing HIV-1 and HIV-2 infection: lessons for viral immunopathogenesisRev Med Virol. 2013;23(4):221-240. doi:10.1002/rmv.1739

  6. Centers for Disease Control and Prevention. About HIV.

  7. Food and Drug Adminstration. About HIV and the Center for Drug Evaluation and Research's role.

  8. HIV.gov. Guidelines for the use of antiretroviral agents in adults and adolescents living with HIV.

  9. World Health Organization. HIV/AIDS.

  10. MedlinePlus. Lactic acidosis.

  11. ScienceDirect. Lactic acidosis.

  12. National Institute of Neurological Disorders and Stroke. Myopathy.

  13. National Institute of Diabetes and Digestive and Kidney Diseases. Hepatitis B.

  14. LactMed. Lamivudine.

  15. LactMed. Zidovudine.

  16. Ghany MG, Morgan TR, AASLD-IDSA Hepatitis C Guidance Panel. Hepatitis C guidance 2019 update: American Association for the Study of Liver Diseases—Infectious Diseases Society of America recommendations for testing, managing, and treating hepatitis C virus infection. Hepatology. 2020;71(2):686-721. doi:10.1002/hep.31060

  17. Prescribers' Digital Reference. Lamivudine/zidovudine - drug summary.

  18. Food and Drug Administration. Drugs@FDA: FDA-approved drugs.

  19. Centers for Disease Control and Prevention. Healthy living with HIV.

By Ross Phan, PharmD, BCACP, BCGP, BCPS
Ross is a writer for Verywell with years of experience practicing pharmacy in various settings. She is also a board-certified clinical pharmacist and the founder of Off Script Consults.