Drug information

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Efavirenz / Lamivudine / Tenofovir Disoproxil Fumarate
Brand Name
Symfi Lo (brand product discontinued), Symfi
Other Names
Efavirenz / Lamivudine / Tenofovir DF, EFV/3TC/TDF
Drug Class
Combination Drugs
Non-Nucleoside Reverse Transcriptase Inhibitor (efavirenz)
Nucleoside Reverse Transcriptase Inhibitor (lamivudine, tenofovir DF)
Drug Image(s): (Click to enlarge)
symfi tablet

(The drug image[s] shown above is of the brand product only. There may be other available products not shown.)

What are the most important things to know about efavirenz/lamivudine/tenofovir disoproxil fumarate?What are the most important things to know about efavirenz/lamivudine/tenofovir disoproxil fumarate?

What are the most important things to know about efavirenz/lamivudine/tenofovir disoproxil fumarate?

Efavirenz/lamivudine/tenofovir DF can cause serious, life-threatening side effects. These include a buildup of lactic acid in the blood (lactic acidosis), liver problems, new or worsening kidney problems, including kidney failure, mental health problems, and severe skin rash and allergic reactions.

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

  • Weakness or tiredness
  • Unusual muscle pain
  • Shortness of breath or fast breathing
  • Stomach pain with nausea and vomiting
  • Cold or blue hands and feet
  • Dizziness or lightheadedness
  • Fast or abnormal heartbeat

Some people taking efavirenz, a component of efavirenz/lamivudine/tenofovir DF, may develop liver problems. People with a history of hepatitis B virus infection (HBV) or hepatitis C virus infection (HCV) or who have elevated results on liver function tests may have an increased risk of developing new or worsening liver problems while taking efavirenz/lamivudine/tenofovir DF. Liver problems have also occurred in people without a history of liver problems or other risk factors. Liver function tests may be done before and during treatment with efavirenz/lamivudine/tenofovir DF.

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
  • Nausea or vomiting
  • Pain, aching, or tenderness on the right side of your stomach/abdominal area
  • Itching

If you have both HIV and HBV and take efavirenz/lamivudine/tenofovir DF, your HBV may get much worse (flare up) if you stop taking efavirenz/lamivudine/tenofovir DF. Do not stop taking efavirenz/lamivudine/tenofovir DF without first talking to your health care provider. If you stop taking efavirenz/lamivudine/tenofovir DF, you will need blood tests regularly for several months to check your liver function and monitor your HBV.

Contact your health care provider right away if you have any of the following symptoms that could be signs of a worsening kidney problem (called Fanconi Syndrome), which may be related to tenofovir-containing drugs:

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

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

  • Feeling sad or hopeless
  • Feeling anxious or restless
  • Not trusting other people
  • Hearing or seeing things that are not real
  • Not being able to move or speak normally
  • Harming yourself or others, or having thoughts about harming yourself (including suicidal thoughts)
  • Not being able to tell the difference between what is true or real and what is false or unreal

Contact your health care provider right away if you develop a rash while taking efavirenz/lamivudine/tenofovir DF. Stop taking efavirenz/lamivudine/tenofovir DF and get medical help right away if you develop a rash with any of the following symptoms:

  • General ill feeling
  • Extreme tiredness
  • Muscle or joint aches
  • Fever
  • Blistering or peeling skin
  • Blisters or sores in your mouth
  • Redness or swelling of the eyes (conjunctivitis)
  • Swelling of your face, lips, mouth, tongue or throat
  • Trouble breathing or swallowing

While taking efavirenz/lamivudine/tenofovir DF, it is important to keep all of your appointments with your health care provider.

What is efavirenz/lamivudine/tenofovir disoproxil fumarate?What is efavirenz/lamivudine/tenofovir disoproxil fumarate?

What is efavirenz/lamivudine/tenofovir disoproxil fumarate?

Efavirenz/lamivudine/tenofovir DF is a prescription medicine approved by the U.S. Food and Drug Administration (FDA) for the treatment of HIV in adults and children weighing at least 77 lb (35 kg).

Efavirenz/lamivudine/tenofovir DF is a complete HIV treatment regimen and should not be used with other HIV medicines.

Efavirenz/lamivudine/tenofovir DF contains three different medicines: efavirenz, lamivudine, and tenofovir disoproxil fumarate.

For more information on the use of efavirenz/lamivudine/tenofovir DF in people with HIV, please refer to the Guidelines for the Use of Antiretroviral Agents in Adults and Adolescents With HIV and the Guidelines for the Use of Antiretroviral Agents in Pediatric HIV Infection.

HIV medicines cannot cure HIV/AIDS, but using HIV medicines as directed by a health care provider helps people with HIV live longer, healthier lives. HIV medicines also reduce the risk of HIV transmission. If you are using HIV medicines, do not cut down on, skip, or stop using them unless your health care provider tells you to.

What should I tell my health care provider before taking efavirenz/lamivudine/tenofovir disoproxil fumarate?What should I tell my health care provider before taking efavirenz/lamivudine/tenofovir disoproxil fumarate?

What should I tell my health care provider before taking efavirenz/lamivudine/tenofovir disoproxil fumarate?

Before taking efavirenz/lamivudine/tenofovir DF, tell your health care provider:

  • If you are allergic to any of the HIV medicines in efavirenz/lamivudine/tenofovir DF (efavirenz, lamivudine, and tenofovir disoproxil fumarate) or any other medicines.
  • If you have liver problems, including hepatitis B virus infection (HBV) or hepatitis C virus infection (HCV).
  • If you have kidney problems, including end-stage renal disease (ESRD) that requires dialysis.
  • If you have a history of mental health problems.
  • If you have a history of drug or alcohol abuse.
  • If you have a heart problem, including QT prolongation.
  • If you have bone problems, including a history of bone fractures.
  • If you have a history of seizures.
  • If you have any other medical conditions.
  • If you are pregnant or plan to become pregnant. Talk to your health care provider about the risks and benefits of taking efavirenz/lamivudine/tenofovir DF during pregnancy. For more information on the use of efavirenz/lamivudine/tenofovir DF during pregnancy, please refer to the Recommendations for the Use of Antiretroviral Drugs During Pregnancy and Interventions to Reduce Perinatal HIV Transmission in the United States.
  • If you are breastfeeding or plan to breastfeed. For mothers with HIV in the United States, the Guideline recommends speaking with your health care provider to discuss options for feeding your baby. Mothers with suppressed viral load have a less than 1% chance of transmitting HIV to their baby via their own milk. Although most medicines are safe to use while breastfeeding, some medicines should be avoided. Always let your health care provider know about all the medicines and supplements you are using before you start breastfeeding.
  • 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 HIVinfo HIV and Birth Control infographic.
  • About other prescription and nonprescription medicines, vitamins, nutritional supplements, and herbal products (particularly St. John's wort) you are taking or plan to take. Efavirenz/lamivudine/tenofovir DF may affect the way other medicines or products work, and other medicines or products may affect how efavirenz/lamivudine/tenofovir DF works. Taking efavirenz/lamivudine/tenofovir DF together with certain medicines or products may cause serious side effects.

How should I take efavirenz/lamivudine/tenofovir disoproxil fumarate?How should I take efavirenz/lamivudine/tenofovir disoproxil fumarate?

How should I take efavirenz/lamivudine/tenofovir disoproxil fumarate?

Efavirenz/lamivudine/tenofovir DF comes in tablet form in two different strengths:

Take efavirenz/lamivudine/tenofovir DF according to your health care provider’s instructions. Do not miss a dose of efavirenz/lamivudine/tenofovir DF, and do not change your dose or stop taking efavirenz/lamivudine/tenofovir DF without first talking with your health care provider.

Take efavirenz/lamivudine/tenofovir DF on an empty stomach and preferably at bedtime. Taking efavirenz/lamivudine/tenofovir DF at bedtime might help to make some of the side effects less bothersome.

If you have taken too much efavirenz/lamivudine/tenofovir DF, contact your health care provider or local poison control center (1-800-222-1222 or online) right away, or go to the nearest hospital emergency room.

For more information on how to take efavirenz/lamivudine/tenofovir DF, see the FDA drug labels for efavirenz/lamivudine/tenofovir DF tablet (film coated) 400 mg/300 mg/300 mg and tablet (film coated) 600 mg/300 mg/300 mg.

What should I do if I forget a dose?What should I do if I forget a dose?

What should I do if I forget a dose?

If you miss a dose of efavirenz/lamivudine/tenofovir DF, 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 efavirenz/lamivudine/tenofovir disoproxil fumarate cause?What side effects can efavirenz/lamivudine/tenofovir disoproxil fumarate cause?

What side effects can efavirenz/lamivudine/tenofovir disoproxil fumarate cause?

Efavirenz/lamivudine/tenofovir DF may cause side effects. Some side effects of efavirenz/lamivudine/tenofovir DF can be serious as noted above. Many side effects from HIV medicines, such as nausea or occasional dizziness, are manageable. See the HIVinfo fact sheet on HIV Medicines and Side Effects for more information.

Other possible side effects of efavirenz/lamivudine/tenofovir DF include:

  • Nervous system symptoms (including dizziness, trouble concentrating, drowsiness, trouble sleeping, unusual dreams, lack of coordination or balance, delusions, and hallucinations).
  • Inflammation of the pancreas (pancreatitis) in some children. Contact your healthcare provider right away if your child develops signs and symptoms of pancreatitis, including severe pain in the upper stomach/abdominal area, with or without nausea and vomiting.
  • Seizures, which are more likely to happen if you have had seizures in the past.
  • Increases in blood fat levels, such as cholesterol and triglycerides.
  • Bone problems, including bone pain, or softening or thinning of the bones (osteopenia), which may lead to fractures.
  • 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 (lipodystrophy syndrome).
  • QT prolongation, which is a heart disorder that causes irregular heartbeats. QT prolongation can be life-threatening. Contact your healthcare provider if you feel faint, lightheaded, dizzy, or feel your heart beating irregularly or fast during treatment with efavirenz/lamivudine/tenofovir DF.

Tell your healthcare 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 efavirenz/lamivudine/tenofovir DF. To learn more about possible side effects of efavirenz/lamivudine/tenofovir DF, read the drug labels or package inserts for efavirenz/lamivudine/tenofovir DF tablet (film coated) 400 mg/300 mg/300 mg and tablet (film coated) 600 mg/300 mg/300 mg 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.

How should efavirenz/lamivudine/tenofovir disoproxil fumarate be stored?How should efavirenz/lamivudine/tenofovir disoproxil fumarate be stored?

How should efavirenz/lamivudine/tenofovir disoproxil fumarate be stored?

  • Store efavirenz/lamivudine/tenofovir DF 400 mg/300 mg/300 mg tablets at room temperature, 68°F to 77°F (20°C to 25°C).
  • Store efavirenz/lamivudine/tenofovir DF 600 mg/300 mg/300 mg tablets below 86°F (30°C).
  • Keep efavirenz/lamivudine/tenofovir DF 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 efavirenz/lamivudine/tenofovir DF if the original seal over the container opening is broken or missing.
  • Throw away efavirenz/lamivudine/tenofovir DF that is no longer needed or expired (out of date). Follow FDA guidelines on how to safely dispose of unused medicine.
  • Keep efavirenz/lamivudine/tenofovir DF and all medicines out of reach of children.

Where can I find more information about efavirenz/lamivudine/tenofovir disoproxil fumarate?Where can I find more information about efavirenz/lamivudine/tenofovir disoproxil fumarate?

Where can I find more information about efavirenz/lamivudine/tenofovir disoproxil fumarate?

Manufacturer Information

Symfi brand product

Viatris

Main number: 724-514-1800

Generic product(s)

For manufacturer information on a generic efavirenz/lamivudine/tenofovir DF product, please refer to the generic drug label or the manufacturer’s website.

Last Reviewed: June 2, 2025