Symfi (Efavirenz/Lamivudine/Tenofovir Disoproxil Fumarate)

Symfi (efavirenz/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 40 kilograms.

How Symfi Works and How It’s Taken

Symfi contains three antiviral medicines in one tablet: efavirenz, lamivudine, and tenofovir disoproxil fumarate. Together, they are used as a complete treatment for HIV-1.

The three medicines work by blocking reverse transcriptase. This is an enzyme that HIV-1 needs to make new copies of itself. Blocking this enzyme helps stop HIV-1 from multiplying.

Doctors prescribe it in adults and children who weigh at least 40 kilograms and can swallow a solid tablet.

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

Symfi is taken by mouth once a day on an empty stomach, preferably at bedtime. Taking it at bedtime may help make nervous system side effects easier to tolerate.

Typical Dosing for HIV

Each Symfi tablet contains:

600 milligrams of efavirenz
300 milligrams of lamivudine
300 milligrams of tenofovir disoproxil fumarate

The recommended dose is one tablet by mouth once daily on an empty stomach, preferably at bedtime.

Symfi is not recommended for people with creatinine clearance below 50 milliliters per minute, people with end-stage kidney disease who need hemodialysis, or people with moderate or severe liver impairment.

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

Symfi Side Effects

In clinical studies of Symfi for treatment of HIV-1, the most common side effects include:

Rash
Dizziness
Headache
Pain
Insomnia (trouble sleeping)
Abnormal dreams
Nausea
Diarrhea
Tiredness or weakness
Trouble concentrating
Depression
Cough

Serious Side Effects and Warnings

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

Severe worsening of hepatitis B after stopping treatment — A serious flare of hepatitis B in people who have both HIV-1 and hepatitis B can occur.
Lactic acidosis and severe liver problems — A buildup of lactic acid in the blood can occur, sometimes with an enlarged, fatty liver.
New or worsening kidney problems — These problems can include acute kidney failure and Fanconi syndrome, a kidney tubule problem that can affect body salts and minerals.
Serious mental health symptoms — These problems can include severe depression, suicidal thoughts or attempts, paranoia, or psychosislike symptoms.
Nervous system problems — These problems include trouble with balance or coordination, called ataxia, or encephalopathy, a serious brain condition.
Embryo-fetal toxicity — If you are pregnant, this medication can harm your baby, especially if used during the first trimester of pregnancy.
Severe skin and allergic reactions — These can include blistering rashes, Stevens-Johnson syndrome, or rash with fever and mouth sores.
Liver injury — These problems can include hepatitis and serious liver failure.
Pancreatitis — Inflammation of the pancreas can occur, and children with certain risk factors may have a higher risk.
Seizures — Convulsions can occur.
Bone loss and mineralization problems — These problems can include osteomalacia, softening of bones, sometimes linked to kidney tubule problems.
Immune reconstitution syndrome — New or worsening inflammation can occur as the immune system gets stronger after starting HIV treatment.
Fat redistribution — Changes in where body fat is stored can occur, such as more fat around the belly or upper back or less fat in the arms, legs, or face.
QTc prolongation — Change in the electrical activity of the heart that can cause dangerous irregular heartbeats.

Get medical help right away if you think you are having a serious reaction. If you or someone you know needs help, you can contact the 988 Suicide & Crisis Lifeline by calling or texting 988 or by using the online chat.

What To Know Before Taking Symfi

Before you start Symfi, your doctor will check for hepatitis B virus infection.

Your doctor should also check your kidney and liver health before treatment and during treatment as needed. These tests may include:

Serum creatinine
Serum phosphorus
Estimated creatinine clearance
Urine glucose
Urine protein
Liver function

Before you take this medicine, 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 a history of mental health problems
Have a history of drug or alcohol abuse
Have a heart problem, including QT prolongation
Have bone problems or a history of bone fractures
Have a history of seizures
Are allergic to efavirenz, lamivudine, tenofovir disoproxil fumarate, or any ingredient in Symfi
Are pregnant, plan to become pregnant, or think you may be 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. Some medicines can interact with Symfi.

Do not take Symfi if you have had an allergic reaction to any of its ingredients or if you are taking elbasvir and grazoprevir.

Do not miss doses or let your supply of Symfi run out. Missing doses may allow the virus to increase and can make HIV-1 harder to treat.

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

Efavirenz, one of the medicines in Symfi, may harm an unborn baby and should not be used during the first trimester of pregnancy.

If you can become pregnant, your healthcare provider should do a pregnancy test before you start Symfi. Use effective birth control while taking Symfi and for 12 weeks after stopping it. A barrier method, such as a condom, should always be used together with another form of birth control.

Tell your doctor right away if you become pregnant or think you may be pregnant during treatment.

A pregnancy registry collects information about people who take Symfi during pregnancy and their babies. Healthcare providers can register pregnancies by visiting the Antiretroviral Pregnancy Registry or calling 800-258-4263.

Do not breastfeed while taking Symfi. People with HIV-1 should not breastfeed because HIV-1 can be passed to a baby through breast milk.

Community FAQs

These answers are fact-checked by our editorial staff.

How effective is Symfi for HIV?

In one study of adults with HIV-1 who had not taken HIV medicines before, 79 percent of people taking the three medicines in Symfi achieved and maintained an HIV-1 viral load below 400 copies per milliliter through 48 weeks. Viral load means the amount of HIV in the blood. At 144 weeks, 68 percent had achieved and maintained this level.

Through 144 weeks, 62 percent of people achieved and maintained an HIV-1 viral load below 50 copies per milliliter. Their average CD4-positive cell count increased by 263 cells per cubic millimeter from the start of the study. CD4-positive cells are immune cells that help the body fight infections.

How long does Symfi take to work for HIV?

The study reports HIV-1 treatment results at 48 weeks and 144 weeks. It does not give an exact number of days for when Symfi starts lowering HIV-1 levels.

Efavirenz, one of the three medicines in Symfi, reaches steady blood levels in about six to 10 days. This does not mean that Symfi reaches its full HIV-1 treatment effect within six to 10 days.

Can Symfi interact with other medicines?

Yes. Symfi can interact with many prescription medicines, over-the-counter medicines, and herbal products. These interactions can make Symfi or another medicine work less well, and some can increase the risk of side effects.

Important examples include medicines that affect heart rhythm or kidney function, seizure medicines, some antidepressants, antifungal medicines, hepatitis C medicines, hormonal birth control, certain cholesterol medicines, and some medicines that lower the immune system. St. John’s wort can also interact with Symfi.

Do not take Symfi with elbasvir and grazoprevir. Symfi also should not be taken with other antiretroviral medicines for HIV-1 because it is already a complete HIV-1 treatment regimen.

When possible, avoid medicines that contain sorbitol because sorbitol can lower the amount of lamivudine in the body.

Tell your healthcare provider and pharmacist about everything you take, including prescription medicines, over-the-counter medicines, vitamins, and herbal supplements.