An Overview of Cimduo (Lamivudine/Tenofovir Disoproxil Fumarate)

Brand Name: Cimduo
Other Names: 3TC/TDF, Lamivudine/Tenofovir Disoproxil Fumarate
Drug Class: Nucleoside Reverse Transcriptase Inhibitors


Cimduo can cause serious, life-threatening side effects. These include a buildup of lactic acid in the blood (lactic acidosis), severe liver problems, and new or worse kidney problems.

Contact your health care provider right away if you have any of the following symptoms that could be signs of lactic acidosis:

  • Feeling very weak or tired
  • Unusual (not normal) muscle pain
  • Trouble breathing
  • Stomach pain with nausea and vomiting
  • Feeling cold, especially in your arms and legs
  • Feeling dizzy or lightheaded
  • Fast or irregular heartbeat

Contact your health care provider right away if you have any of the following symptoms that could be signs of liver problems:

  • Yellowing of your skin or the whites of your eyes (jaundice)
  • Dark-colored urine
  • Light-colored bowel movements
  • Loss of appetite for several days or longer
  • Feeling sick to your stomach (nausea and vomiting)
  • Pain, aching, or tenderness on the right side of your stomach area

If you have both HIV and hepatitis B virus infection (HBV) and take Cimduo, your HBV infection may get worse (flare up) if you stop taking Cimduo. To help avoid this, take Cimduo exactly as prescribed. Do not run out of Cimduo or stop taking Cimduo without talking to your health care provider.

Worsening of liver disease (sometimes resulting in death) has occurred in people being treated for hepatitis C virus infection (HCV) taking HIV medicines and interferon alfa with or without ribavirin. If you are taking Cimduo and interferon alfa with or without ribavirin and you have any new symptoms, tell your health care provider.

Some people taking Cimduo have developed new or worse kidney problems, including kidney failure. Your health care provider may do blood and urine tests to check your kidneys before and during treatment with Cimduo.

Contact your health care provider right away if you have any of the following symptoms that could be signs of kidney problems:

  • Bone pain that does not go away or worsening bone pain
  • Pain in your arms, hands, legs or feet
  • Broken bones
  • Muscle pain or weakness

While taking Cimduo, it is important to keep all of your appointments with your health care provider.

What Is Cimduo?

Cimduo is a prescription medicine approved by the U.S. Food and Drug Administration (FDA) to treat HIV infection in adults and children weighing at least 77 pounds (35 kg). Cimduo is always used in combination with other HIV medicines.

Cimduo contains the following two different medicines combined in one pill:

NRTIs block an HIV enzyme called reverse transcriptase. (An enzyme is a protein that starts or increases the speed of a chemical reaction.) By blocking reverse transcriptase, NRTIs prevent HIV from multiplying and can reduce the amount of HIV in the body.

HIV medicines can't cure HIV/AIDS, but taking a combination of HIV medicines (called an HIV regimen) every day helps people with HIV live longer, healthier lives. HIV medicines also reduce the risk of HIV transmission. If you are taking HIV medicines, including Cimduo, don't cut down on, skip, or stop taking them unless your health care provider tells you to.

What Should I Tell My Health Care Provider Before Taking Cimduo?

Before taking Cimduo, tell your health care provider:

  • If you are allergic to any of the HIV medicines in Cimduo (lamivudine and tenofovir disoproxil fumarate) or any other medicines.
  • If you have or have ever had liver problems, including HBV infection or HCV infection.
  • If you have or have ever had kidney problems, including end-stage renal disease (ESRD) that requires dialysis.
  • If you have bone problems, including a history of bone fractures.
  • If you have any other medical conditions.
  • If you are pregnant or plan to become pregnant. Whether Cimduo can harm an unborn baby is unknown. Talk to your health care provider about possible risks with taking Cimduo when pregnant.
  • If you are breastfeeding or plan to breastfeed. Do not breastfeed if you have HIV or are taking Cimduo.
  • If you are using hormone-based birth control (such as pills, implants, or vaginal rings). For more information about using birth control and HIV medicines at the same time, view the AIDSinfo HIV and Birth Control infographic.
  • About other prescription and nonprescription medicines, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Cimduo may affect the way other medicines or products work, and other medicines or products may affect how Cimduo works. Taking Cimduo together with certain medicines or products may cause serious side effects.

How Should I Take Cimduo?

Cimduo comes in tablet form. Each tablet contains:

  • 300 mg lamivudine (brand name: Epivir)
  • 300 mg tenofovir disoproxil fumarate (brand name: Viread)

Take Cimduo according to your health care provider's instructions.

Take Cimduo with or without food.

Always take Cimduo in combination with other HIV medicines.

If you take too much Cimduo, contact your health care provider or local poison control center (1-800-222-1222) right away, or go to the nearest hospital emergency room.

For more information on how to take Cimduo, see the FDA drug label from Drugs@FDA.

What Should I Do if I Forget a Dose?

If you miss a dose of Cimduo, take the missed dose as soon as you remember it. But if it is almost time for your next dose, skip the missed dose and just take your next dose at the regular time. Do not take two doses at the same time to make up for a missed dose.

What Side Effects Can Cimduo Cause?

Cimduo may cause side effects. Many side effects from HIV medicines, such as nausea or occasional dizziness, are manageable. See the AIDSinfo fact sheet on HIV Medicines and Side Effects for more information.

Some side effects of Cimduo can be serious. Serious side effects of Cimduo include a buildup of lactic acid in the blood (lactic acidosis), severe liver problems, and new or worse kidney problems. (See the WARNING box above.)

Other possible side effects of Cimduo include:

  • nflammation of the pancreas (pancreatitis). Contact your health care provider right away if your child develops signs and symptoms of pancreatitis including severe upper stomach-area pain, with or without nausea and vomiting.
  • Bone problems (bone pain, softening or thinning).
  • Changes in your immune system (called immune reconstitution inflammatory syndrome or IRIS). IRIS is a condition that sometimes occurs when the immune system begins to recover after treatment with an HIV medicine. As the immune system gets stronger, it may have an increased response to a previously hidden infection.
  • Changes in body fat, including gain or loss of fat.

Tell your health care provider if you have any side effect that bothers you or that does not go away.

These are not all the possible side effects of Cimduo. To learn more about possible side effects of Cimduo, read the drug label or package insert or talk to your health care provider or pharmacist.

You can report side effects to FDA at 1-800-FDA-1088 (1-800-332-1088) or online at

How Should Cimduo Be Stored?

  • Store Cimduo at room temperature, 68°F to 77°F (20°C to 25°C).
  • Keep Cimduo in the container that it came in and keep the container tightly closed. If the container has a small packet of drying agent (called a desiccant), do not remove it. The desiccant protects the medicine from moisture.
  • Do not use Cimduo if the original seal over the container opening is broken or missing.
  • Throw away Cimduo that is no longer needed or expired (out of date). Follow FDA guidelines on how to safely dispose of unused medicine.
  • Keep Cimduo and all medicines out of reach of children.

Where Can I Find More Information About Cimduo?

More information about Cimduo is available:

  • The Cimduo drug label, from Drugs@FDA. The Patient Counseling Information section of the label includes information for people taking Cimduo.
  • Cimduo-related research studies, from the AIDSinfo database of study summaries.
  • A list of FDA-approved HIV medicines, from AIDSinfo.

Manufacturer Information

Main number: 724-514-1800
Patient assistance: 877-446-3679

Robert J. Coury Global Center
1000 Mylan Blvd.
Canonsburg, PA 15317

The above Patient Version drug summary is based on the following FDA label(s): Tablet (film coated).

[Note from TheBody: This article was created by AIDSinfo, who last updated it on Apr. 5, 2018. We have cross-posted it with their permission.]