Epivir (Lamivudine) – Oral


Epivir (lamivudine) has a boxed warning advising consumers about the risk of a severe flare-up of hepatitis B symptoms in people who discontinue treatment.

What Is Epivir?

Epivir (lamivudine) is an oral drug used to treat human immunodeficiency virus (HIV), chronic hepatitis B infection, or both.

Epivir belongs to a class of medications known as nucleoside reverse transcriptase inhibitors (NRTIs). It works by blocking an enzyme that HIV and the hepatitis B virus (HBV) use to make copies of themselves. Without the means to replicate, the viral population is reduced to levels where it can do the body less harm.

Epivir is available as a tablet or oral solution. When used for the treatment of hepatitis B, the drug is given at a lower dose formulation called Epivir-HBV. Generic versions are also available under the drug name lamivudine.

Drug Facts

Generic Name: Lamivudine

Brand Name(s): Epivir, Epivir A/F, Epivir HBV

Administration Route(s): Oral

Drug Availability: Prescription

Therapeutic Classification: Antiviral, antiretroviral agent

Available Generically: Yes

Controlled Substance: N/A

Active Ingredient: Lamivudine

Dosage Form(s): Tablet, solution

What Is Epivir Used for?

Epivir does not cure HIV or hepatitis B. The goal of treatment is to suppress the virus to where it is undetectable (below the level of detection on blood tests). Doing so slows the progression of the disease.

The Food and Drug Administration (FDA) approved Epivir for the treatment of:

  • HIV: Used in combination with at least one other antiretroviral drug in adults and children aged 3 months and over
  • Chronic hepatitis B: Used on its own in adults and children age 2 years and over

People coinfected with HIV and HBV can use Epivir but only as part of a combination antiretroviral therapy. Although Epivir is initially effective as a single therapy for HIV infection, resistance can develop within 12 weeks of taking it. Therefore, it is optimal to use Epivir as part of a three-drug regimen.

Epivir (Lamivudine) Drug Information - A person with virus particles in the blood stream

Verywell / Dennis Madamba

How to Take Epivir

Epivir and Epivir-HBV are both available as oral tablets. The tablet is taken by mouth once daily with or without food. If you have difficulty swallowing pills, the tablet can be crushed, added to a small amount of semisoft food or liquid, and consumed immediately.

An oral solution is also available for younger children or adults who cannot swallow tablets. Measure each dose with a calibrated dosing spoon or syringe to ensure you take or give the correct dose.

Epivir and Epivir-HBV differ by their strength in milligrams (mg):

  • Epivir tablets contain 150 mg of lamivudine
  • Epivir oral solution contains 10 mg of lamivudine per milliliter
  • Epivir-HBV tablets contain 100 mg of lamivudine
  • Epivir-HBV oral solution contains 5 mg of lamivudine per milliliter


You can safely store Epivir tablets at room temperature between 59 and 86 degrees Fahrenheit. Epivir oral solution needs to be stored at a slightly lower temperature between 68 and 77 degrees F.

Avoid storing Epivir in your glove compartment or on a sunny windowsill, where temperatures can be excessive. Keep the drug tightly sealed in its original light-resistant container. Discard any that have expired. Unused or expired medication drop boxes are often available at a local police station or town/city hall. You can reach out to your pharmacist to ask about proper disposal if drop boxes are not available.

Off-Label Uses

Although not formally approved by the FDA for such use, Epivir can also be used as part of a preventive strategy known as HIV postexposure prophylaxis (PEP). The aim of PEP is to avert an infection if you have been accidentally exposed to HIV, either through unprotected sex, shared needles, or an occupational healthcare injury (such as a needlestick injury).

When used for PEP, Epivir is prescribed with two other antiretroviral drugs. Among the recommended combinations, Epivir is typically used with Viread (tenofovir disoproxil fumarate) and either Isentress (raltegravir) or Tivicay (dolutegravir).

PEP must be started within 72 hours of exposure—ideally less—and taken for 28 consecutive days.

What Are the Side Effects of Epivir?

As with all drugs, Epivir may cause side effects. Most are relatively mild, usually resolving within several days or weeks. In rare cases, Epivir has been known to trigger severe and potentially life-threatening side effects, particularly in people with underlying health issues.

This is not a complete list of side effects and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or a medical professional. You may report side effects to the FDA at www.fda.gov/medwatch or 800-FDA-1088.

Common Side Effects

Epivir is generally well tolerated and may not cause any side effects at all. If side effects do occur, they most commonly involve (by the general order of frequency):

  • Headache
  • Nausea
  • Malaise (a general feeling of being unwell)
  • Fatigue
  • Nasal symptoms
  • Diarrhea
  • Cough

Other side effects reported in clinical studies include:

  • Digestive issues, including vomiting, abdominal pain, and loss of appetite
  • Nervous system issues, including nerve pain, insomnia, dizziness, and depression
  • Musculoskeletal issues, including joint stiffness and muscle aches and pain
  • Rash
  • Fever

Side effects tend to be relatively mild and resolve on their own without treatment. If side effects persist, worsen, or seem unusual, call your healthcare provider.

Severe Side Effects

Epivir can cause severe side effects in some people. These side effects may develop when treatment is started, when treatment is stopped, or when the drug is used for a long time.

Hepatitis B Exacerbation

Epivir carries a black box warning advising consumers about the risk of a severe flare-up of hepatitis B symptoms in people who discontinue treatment. The discontinuation can cause the hepatitis B virus to rebound to very high levels. In people with advanced liver disease, including cirrhosis, this could lead to liver failure.

Before starting treatment, the FDA recommends hepatitis B testing to identify undiagnosed infections. If Epivir is discontinued, people with hepatitis B should be closely monitored and provided anti-hepatitis B drugs, if needed, to reduce the risk of an exacerbation (flare-up).

Lactic Acidosis

Lactic acidosis is the buildup of lactic acid in the blood. The condition, while rare, is associated with nucleoside drugs in the same class as Epivir. If lactic acidosis occurs and the treatment is not stopped immediately, the acid buildup can be fatal.

Lactic acidosis can develop months or even years after the start of treatment. People with impaired kidney function and those with advanced HIV at the beginning of treatment (defined by a low CD4 count, which are white blood cells) are at the greatest risk. Even so, anyone who takes an NRTI can get lactic acidosis.


Epivir may rarely cause pancreatitis (inflammation of the pancreas). People with a history of pancreatitis or children with previous exposure to nucleoside drugs are at the highest risk. Stop treatment immediately if symptoms of pancreatitis develop.

Immune Reconstitution Inflammatory Syndrome

Immune reconstitution inflammatory syndrome (IRIS) is a rare but serious inflammatory reaction typically affecting people who start HIV therapy with a low CD4 count.9 The reaction can occur with any combination of HIV drugs, including one containing Epivir.

IRIS occurs when the immune system starts to recover with HIV therapy but responds with a massive inflammatory reaction to a co-occurring infection like tuberculosis or cryptococcosis. In some cases, the accompanying opportunistic infection (OI) will be undiagnosed and “unmasked” by the inflammatory response. IRIS can occur within the first days or first six months of starting HIV therapy. With cryptococcal meningitis especially, IRIS can be fatal.

Call your healthcare provider right away if you have serious side effects after using Epivir. Call 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency. These include symptoms of lactic acidosis, pancreatitis, and HBV reactivation, such as:

Long-Term Side Effects

The long-term use of NRTIs like Epivir can cause metabolic problems and damage nerve cells. Although these complications are more commonly linked to older NRTIs like Zerit (stavudine), they can sometimes affect Epivir users.

Because these complications are difficult to reverse, it is important to recognize the signs so that treatment can be stopped before they become severe.

Peripheral Neuropathy

Some people who take NRTIs like Epivir may develop a condition called peripheral neuropathy. Peripheral neuropathy is characterized by pins-and-needles or burning sensations in the hands or feet due to the destruction of the protective coating of nerve cells, called the myelin sheath.

If left untreated, peripheral neuropathy can become severe and interfere with walking and a person’s quality of life. Although discontinuing the drug can improve symptoms, it may not be able to reverse it if the condition is severe.


The long-term use of NRTIs like Epivir can cause a condition known as lipodystrophy in which fat is redistributed abnormally in the body. 

With HIV lipodystrophy, there will often be a thinning of the face, buttocks, arms, and legs and an increase of fat in the abdomen, breasts, and back of the neck (referred to as a buffalo hump).

Lipodystrophy is more commonly associated with Zerit and older protease inhibitors like Crixivan (indinavir) but can also occur with Epivir (although usually not as profoundly). Because lipodystrophy may not be reversible, particularly when at an advanced stage, it is important to stop treatment and switch to other available drugs as soon as possible.

Report Side Effects

Epivir may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Epivir Should I Take?

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The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage forms (solution or tablets):
    • For treatment of hepatitis B infection:
      • Adults—100 milligrams (mg) once a day.
      • Children 2 to 17 years of age—Dose is based on body weight and must be determined by your doctor. The dose is usually 3 milligrams (mg) per kilogram (kg) of body weight per day. The doctor may increase your dose as needed. However, the dose is usually not more than 100 mg per day. If your child cannot swallow the tablets, he or she may take the oral liquid.
      • Children younger than 2 years of age—Use and dose must be determined by your doctor.
    • For treatment of HIV infection or AIDS:
      • Adults—300 milligrams (mg) once a day or 150 mg 2 times a day.
      • Children 3 months of age and older—
        • Solution: Dose is based on body weight and must be determined by your doctor. The dose is usually 5 milligrams (mg) per kilogram (kg) of body weight taken 2 times a day, or 10 mg per kg once a day. The doctor may increase your dose as needed. However, the dose is usually not more than 300 mg per day, taken with other HIV medicines.
        • Tablets: Dose is based on body weight and must be determined by your doctor. The dose is usually 150 to 300 mg per day. If your child weighs 14 kg or more, it is preferred that he or she take the scored tablet.
      • Children younger than 3 months of age—Use and dose must be determined by your doctor.

Note: Patients that require treatment for both hepatitis B and either AIDS or HIV should follow the dosing schedule for HIV or AIDS.


Epivir is mainly excreted from the body in urine. Because of this, people with kidney dysfunction may require a dose adjustment to avoid the toxic buildup of the drug in the bloodstream.

The modified dose is based on a test called creatinine clearance (CrCl) that indicates how well the kidneys are working based on the amount of a waste product called creatinine excreted in urine. The CrCl results are measured in values of milliliters per minute (mL/min).

For people prescribed Epivir, the dose is adjusted as follows:

  • CrCl 30 to 49 mL/min: 150 mg once daily
  • CrCl 15 to 29 mL/min: 150 mg for the first dose, then 100 mg daily
  • CrCl 5 to 14 mL/min: 150 mg for the first dose, then 50 mg daily
  • CrCl under 5 mL/min: 50 mg for the first dose, then 25 mg daily

For people prescribed Epivir-HBV, the dose is adjusted as follows:

  • CrCl 30 to 49 mL/min: 100 mg for the first dose, then 50 mg daily
  • CrCl 15 to 29 mL/min: 100 mg for the first dose, then 25 mg daily
  • CrCl 5 to 14 mL/min: 35 mg for the first dose, then 15 mg daily
  • CrCl under 5 mL/min: 35 mg for the first dose, then 10 mg daily

Missed Dose

If you miss a dose of Epivir, take it as soon as you remember. If it is almost time for your next dose, skip the original dose and continue as normal. Never double up doses.

It is important that you take Epivir every day as prescribed. If you don’t, you run the risk of developing drug resistance in which your medications become less and less effective.

Overdose: What Happens If I Take Too Much Epivir?

An Epivir overdose can be serious and trigger potentially life-threatening lactic acidosis. If an overdose were to occur, the treatment would be largely focused on the management of symptoms, including nausea, vomiting, diarrhea, irregular heartbeats, and breathing difficulty.

Oxygen therapy may be needed along with intravenous fluids to promote circulation and prevent shock. It is unclear if kidney dialysis can help clear the drug from the body, but it may be used if there are symptoms of lactic acidosis.

What Happens If I Overdose on Epivir?

If you think you or someone else may have overdosed on Epivir, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Epivir, call 911 immediately.


Drug Content Provided and Reviewed by IBM Micromedex®

It is very important that your doctor check your or your child's progress at regular visits to make sure that this medicine is working properly. Blood and urine tests may be needed to check for unwanted effects.

Do not use this medicine if you or your child is also taking zalcitabine or medicines containing emtricitabine or lamivudine (eg, Atripla®, Combivir®, Complera®, Emtriva®, Epzicom®, Stribild®, Trizivir®, Truvada®). Tell your doctor right away if you are using any of these medicines.

Two rare but serious reactions to this medicine are lactic acidosis (build-up of acid in the blood) and liver toxicity, including an enlarged liver. These are more common if you are female, very overweight (obese), or have been taking anti-HIV medicines for a long time. Call your doctor right away if you or your child has stomach discomfort or cramping, nausea, vomiting, or diarrhea, a decreased appetite, a general feeling of discomfort, muscle cramping or pain, unusual tiredness or weakness, trouble breathing, or yellow skin or eyes.

This medicine may cause worsening of hepatitis B infection when treatment is stopped. Talk to your doctor if you have any concerns about this.

Pancreatitis may occur while you are using Epivir® . Tell your doctor right away if you or your child has sudden and severe stomach pain, chills, constipation, nausea, vomiting, fever, or lightheadedness.

Your immune system may get stronger when you start using Epivir® . This could cause a hidden infection in your body to become active. Tell your doctor right away if you or your child notice any changes in your health.

Lamivudine does not decrease the risk of transmitting HIV infection or hepatitis B infection to others through sexual contact or by contamination through blood. HIV or hepatitis B may be acquired from or spread to others through infected body fluids, including blood, vaginal fluid, or semen. If you are infected, it is best to avoid any sexual activity involving an exchange of body fluids with other people. If you do have sex, always wear (or have your partner wear) a condom (“rubber”). Only use condoms made of latex or polyurethane and use them every time you have contact with semen, vaginal secretions, or blood. Also, do not re-use or share needles or equipment with anyone. If you have any questions about this, check with your doctor.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

What Are Reasons I Shouldn’t Take Epivir?

You should not use Epivir if you've had a prior hypersensitive reaction to lamivudine or any other ingredient in the drug. However, hypersensitive drug reactions to Epivir are rare and more commonly associated with the NRTIs Emtriva (emtricitabine), Retrovir (zidovudine), and Ziagen (abacavir).

What Other Medications Interact With Epivir?

Epivir may interact with other drugs that rely on the kidneys for clearance. The “competition” for clearance may alter the concentration of Epivir or the accompanying drug in the bloodstream. Even so, there are few interactions that are significant to require a dose adjustment or change of treatment.

Three potential drug interactions include sorbitol (sugar alcohol) and interferon alfa (a type of immunotherapy), both of which may reduce Epivir concentrations. The primary concern is with the oral solution dosage form of Epivir and sorbitol. An all-tablet regimen is recommended when possible to avoid this potential interaction.

This is not a complete list of potential drug interactions. To avoid interactions, always tell your healthcare provider about any medications you take, whether they are prescription, over the counter (OTC, without a prescription), nutritional, herbal, or recreational.

What Medications Are Similar?

Epivir belongs to a class of drugs called nucleoside reverse transcriptase inhibitors (NRTIs). They were the first class of drugs used to treat HIV and continue to be among the most effective and durable antiretroviral agents.

In addition to Epivir, there are four other NRTIs used in combination HIV therapy:

  • Emtriva (emtricitabine)
  • Retrovir (zidovudine)
  • Viread (tenofovir disoproxil fumarate)
  • Ziagen (abacavir)

There are also two NRTIs used solely for the treatment of chronic hepatitis B:

Epivir and Viread are the only two drugs licensed to treat both HIV and chronic hepatitis B infection.

Lamivudine, the active ingredient in Epivir, is also a component of several triple combination drugs, including Triumeq (abacavir, dolutegravir, and lamivudine).

How Can I Stay Healthy While Taking Epivir?

Living with HIV or hepatitis B can be challenging. But advances in treatment have not only increased life expectancies but also improved the overall health and quality of life of people living with these diseases.

Today, people living with HIV can expect to live normal to near-normal life expectancies if diagnosed and treated early. In addition, by sustaining an undetectable viral load, the chance of infecting others is reduced to almost zero. Similar advances have been seen with hepatitis B, in which drugs like Epivir have reduced the risk of severe liver complications and extended the lifespan of those who are chronically infected.

But it takes more than just pills to live well with HIV or hepatitis B. Positive lifestyle changes—including a healthy diet, routine exercise, and quitting cigarettes—are essential to preventing heart disease and cancers common in people with HIV. Similarly, avoiding alcohol helps protect your liver if you have hepatitis B.

Let your healthcare provider know if you have any problems with your medications, including side effects that are difficult to tolerate. In some cases, the treatment can be changed or simplified.

You should never stop treatment or adjust the dose without first talking to your healthcare provider. Inconsistent or improper dosing can lead to drug resistance and leave you with fewer treatment options if it does fail.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended as a replacement for medical advice, diagnosis, or treatment from a healthcare professional. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

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By James Myhre & Dennis Sifris, MD
Dennis Sifris, MD, is an HIV specialist and Medical Director of LifeSense Disease Management. James Myhre is an American journalist and HIV educator.