Reviewed on 9/15/2022

What Is Lamivudine and Zidovudine and How Does It Work?

Lamivudine and Zidovudine is a combination medication used to treat human immunodeficiency virus (HIV), the virus that can cause AIDS. Lamivudine and Zidovudine is not a cure for HIV or AIDS. 

  • Lamivudine and Zidovudine are available under various brand names: Combivir

What Are Side Effects Associated with Using Lamivudine and Zidovudine?

Common side effects of Lamivudine and Zidovudine include:

  • headache.
  • nausea, diarrhea.
  • tiredness, general ill feeling.
  • cold symptoms such as stuffy nose, sneezing, sinus pain, cough; or
  • loss of body fat (especially in the arms, legs, face, and buttocks).

Serious side effects of Lamivudine and Zidovudine include:

  • hives. 
  • difficult breathing. 
  • swelling of the face, lips, tongue, or throat,
  • unusual muscle pain, 
  • trouble breathing,
  • stomach pain, 
  • vomiting,
  • irregular heart rate, 
  • dizziness, 
  • feeling cold, 
  • feeling very weak,
  • tired,
  • liver problems--swelling around the midsection, right-sided upper stomach pain, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);
  • low red blood cells (anemia)--pale skin, unusual tiredness, feeling light-headed or short of breath, cold hands, and feet.
  • low white blood cell counts--fever, mouth sores, skin sores, sore throat, cough, trouble breathing; or
  • pancreatitis--severe pain in the upper stomach spreading to the back, nausea, and vomiting.
  • 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 the neck or throat (enlarged thyroid), menstrual changes, impotence.

Rare side effects of Lamivudine and Zidovudine include:

  • none

Seek medical care or call 911 at once if you have the following serious side effects:

  • Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors;
  • Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
  • Serious heart symptoms such as fast, irregular, or pounding heartbeats; fluttering in the chest; shortness of breath; sudden dizziness, lightheartedness, or passing out.

This is not a complete list of side effects and other serious side effects or health problems that may occur because of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

What Are Dosages of Lamivudine and Zidovudine?

Adult and pediatric dosage


  • 150 mg/300 mg

HIV Infection

Adult dosage

  • 150 mg/300 mg (1 tablet) orally every 12 hours
  • Monitor amylase every 4-8 weeks
  • Because of fixed-dose, avoid administering to patients below 30 kg, patients with crcl below 50 ml/min, or in hepatic impairment

Pediatric dosage

  • Children below 12 years: Not recommended; the fixed-dose combination cannot be adjusted for children
  • Children above 12 years and below 30 kg: Not recommended
  • Children above 12 years and above 30 kg: As adults; 150 mg/300 mg (1 tablet) orally every 12 hours
  • Monitor amylase every 4-8weeks

Dosage Considerations – Should be Given as Follows: 

  • See “Dosages”

What Other Drugs Interact with Lamivudine and Zidovudine?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all your products. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions or concerns.

What Are Warnings and Precautions for Lamivudine and Zidovudine?


  • You should not take this medicine if you are allergic to lamivudine. Do not take Combivir with any other medicine that contains lamivudine, zidovudine, or emtricitabine. 
  • Lamivudine and Zidovudine can also cause severe or fatal liver problems. Tell your doctor if you have liver disease, especially hepatitis B.
  • Adolescents weighing less than 66 pounds

Effects of drug abuse

  • None

Short-Term Effects

  • See “What Are Side Effects Associated with Using Lamivudine and Zidovudine?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Lamivudine and Zidovudine?”


  • Do not take this medicine if you have ever had an allergic reaction to any medicine that contains lamivudine or zidovudine.
  • Zidovudine can weaken your immune system and cause signs of infection (fever, mouth sores, skin sores, flu symptoms, pale skin). Your blood will need to be tested often. Long-term use of zidovudine can cause muscle weakness or loss of muscle tissue like "wasting syndrome" caused by HIV.
  • You may develop lactic acidosis, 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.
  • If you've ever had hepatitis B, it may become active or get worse after you stop using this medicine. You may need frequent liver function tests for several months.
  • 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 this medicine 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.

Pregnancy and Lactation

  • 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.
  • Lactation
    • Women with HIV or AIDS should not breastfeed a baby. Even if your baby is born without HIV, the virus may be passed to the baby in your breast milk.

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