Cimduo (Lamivudine/Tenofovir Disoproxil Fumarate) for HIV

Cimduo (lamivudine and tenofovir disoproxil fumarate) is a prescription medication approved by the U.S. Food and Drug Administration (FDA) to treat human immunodeficiency virus type 1 (HIV-1) infection in adults and children who weigh at least 35 kilograms.

How Cimduo Works and How It’s Taken

Cimduo contains two medicines — lamivudine and tenofovir disoproxil fumarate.

These medicines block an enzyme called reverse transcriptase. HIV-1 needs this enzyme to make copies of itself. Blocking this enzyme helps stop HIV-1 from making more copies in the body.

Doctors prescribe Cimduo with other HIV medicines to treat HIV-1 infection in adults and children who weigh at least 35 kilograms.

HIV-1 is the virus that causes acquired immune deficiency syndrome (AIDS).

Cimduo is taken as a tablet by mouth once daily, with or without food.

Typical Dosing for HIV

Each Cimduo tablet contains 300 milligrams of lamivudine and 300 milligrams of tenofovir disoproxil fumarate.

The recommended dose is one tablet taken by mouth once daily.

Cimduo is not recommended for people with creatinine clearance below 50 milliliters per minute or for people with end-stage kidney disease who need hemodialysis. This is because Cimduo is a fixed-dose tablet and the dose cannot be adjusted.

This information is based on prescribing information, but your healthcare provider may tailor your treatment plan. Always follow their guidance.

Cimduo Side Effects

In clinical studies of Cimduo, the most common side effects occurred in about 11 percent to 18 percent of people. These include:

Headache
Pain
Depression
Diarrhea
Rash

Serious Side Effects and Warnings

Cimduo can cause serious side effects that may require immediate medical attention. These include:

Lactic acidosis — Too much lactic acid can build up in the blood, which is a medical emergency.
Severe liver problems — These problems can include enlarged liver and fatty liver (hepatomegaly with steatosis).
Worsening hepatitis B after stopping Cimduo — A hepatitis B flare can occur in people who also have hepatitis B.
New or worsening kidney problems, including kidney failure — These kidney problems may include Fanconi syndrome, a type of kidney tubule injury.
Pancreatitis — Inflammation of the pancreas can occur.
Bone problems — Bone mineral density loss and osteomalacia, which is softening of the bones, can contribute to fractures.
Immune reconstitution syndrome — Immune system changes can trigger inflammation as the body starts fighting infections.
Fat redistribution — Changes in body fat, such as increased belly fat or fat loss in the arms, legs, or face, can occur.
Severe allergic reaction — Hypersensitivity reactions can occur, including anaphylaxis or angioedema, which can cause swelling.

Get medical help right away if you think you are having a serious reaction.

What To Know Before Taking Cimduo

Before starting Cimduo, your doctor will test or check for:

Hepatitis B virus infection
Kidney function, including estimated creatinine clearance
Serum phosphorus, which measures phosphorus in your blood
Glucose in your urine
Protein in your urine

Before taking Cimduo, tell your doctor if you:

Have liver problems, including hepatitis B or hepatitis C
Have kidney problems, including end-stage kidney disease that requires dialysis
Have bone problems, including a history of bone fractures
Have had an allergic reaction to lamivudine, tenofovir disoproxil fumarate, or any ingredient in Cimduo
Are pregnant or plan to become pregnant
Are breastfeeding or plan to breastfeed

Tell your doctor about all medicines you take, including prescription drugs, over-the-counter medicines, vitamins, and herbal supplements.

Do not take Cimduo if you have had a serious allergic reaction to lamivudine/tenofovir disoproxil fumarate or any of its ingredients.

Do not miss doses or let your supply of Cimduo run out. The amount of virus in your blood may increase, and the virus may become harder to treat.

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and take your next dose at the regular time.

A pregnancy exposure registry monitors pregnancy outcomes in people exposed to Cimduo. Healthcare providers can register pregnancies by visiting the Antiretroviral Pregnancy Registry or calling 800-258-4263.

Do not breastfeed if you take Cimduo. HIV-1 can pass to a baby through breast milk.

Community FAQs

These answers are fact-checked by our editorial staff.

How effective is Cimduo for HIV?

In a study of adults starting HIV treatment, people received a treatment regimen that included tenofovir disoproxil fumarate, lamivudine, and efavirenz. The response rate was 79 percent at week 48 and 68 percent at week 144.

Through 144 weeks, 62 percent of people in this group reached and maintained an HIV-1 RNA level below 50 copies per milliliter. This is a measure of the amount of HIV in the blood.

The average CD4 cell count increased by 263 cells per cubic millimeter from the start of the study. CD4 cells are immune cells that HIV can damage.

How long does Cimduo take to work for HIV?

Available clinical study results report outcomes at week 48 and week 144. They do not give an exact earliest time point for when Cimduo starts working.

Can Cimduo interact with other medicines?

Yes. Cimduo can interact with other medicines.

Some medicines can raise the amount of tenofovir in the body or increase the risk of kidney problems. These include certain HIV medicines, hepatitis C medicines, and medicines that affect kidney function. Examples include atazanavir with ritonavir, darunavir with ritonavir, lopinavir with ritonavir, ledipasvir/sofosbuvir, sofosbuvir/velpatasvir, and some high-dose or multiple nonsteroidal anti-inflammatory drugs (NSAIDs).

Medicines that contain sorbitol can lower the amount of lamivudine in the body, so they should be avoided when possible. Cimduo may also interact with medicines that are cleared through the kidneys, such as trimethoprim.

Tell your healthcare provider about all prescription medicines, over-the-counter medicines, vitamins, and herbal supplements you take before starting Cimduo.