Epivir (Lamivudine)
Nucleoside Reverse Transcriptase Inhibitor (NRTI) for HIV Treatment
Quick Facts About Epivir
Key Takeaways
- Epivir (lamivudine) is an NRTI antiretroviral used as part of combination therapy to treat HIV infection in adults and children.
- It reduces viral load and increases CD4 cell counts, helping the immune system recover, but does not cure HIV.
- The standard adult dose is 300 mg daily, taken as one or two doses. Dose adjustments are required for kidney impairment.
- Do not stop Epivir abruptly if you have hepatitis B co-infection, as this can trigger a severe hepatitis flare.
- Common side effects include headache, nausea, fatigue, and diarrhoea. Rare but serious effects include lactic acidosis and pancreatitis.
What Is Epivir and What Is It Used For?
Epivir contains the active substance lamivudine, a synthetic nucleoside analogue that belongs to a group of antiretroviral medicines called nucleoside reverse transcriptase inhibitors (NRTIs). It is approved for the treatment of human immunodeficiency virus (HIV) infection in both adults and children, and is always prescribed as part of combination antiretroviral therapy (cART) alongside other antiretroviral agents.
The mechanism of action of lamivudine involves intracellular phosphorylation to its active form, lamivudine triphosphate. This active metabolite competes with the natural nucleoside substrate (deoxycytidine triphosphate) for incorporation into growing viral DNA chains by the HIV reverse transcriptase enzyme. Once incorporated, it acts as a chain terminator, preventing further elongation of the proviral DNA and thereby halting viral replication.
Clinically, Epivir does not cure HIV infection. Rather, it is a critical component of suppressive therapy that reduces the amount of virus in the blood (viral load) to undetectable levels and allows recovery of the immune system, as evidenced by increasing CD4+ T-lymphocyte counts. The World Health Organization (WHO) includes lamivudine as a key component of its recommended first-line and second-line antiretroviral treatment regimens for both adults and children worldwide.
Not all patients respond to treatment with Epivir in the same way. Your doctor will monitor your response through regular blood tests that measure your viral load and CD4 cell counts. If the treatment is not sufficiently suppressing the virus, your doctor may need to adjust your medication regimen. The development of resistance to lamivudine, particularly through the M184V mutation, is a well-characterised phenomenon that clinicians factor into treatment planning.
Lamivudine is also active against the hepatitis B virus (HBV), and is marketed under the brand name Zeffix specifically for hepatitis B treatment at a different dosage. This dual activity has important clinical implications for patients co-infected with both HIV and HBV, as discontinuation of lamivudine can lead to severe hepatitis B flares.
What Should You Know Before Taking Epivir?
Contraindications
Epivir is contraindicated in patients with a known hypersensitivity to lamivudine or to any of the excipients in the formulation. If you have previously experienced an allergic reaction to lamivudine in any product, you must not take Epivir. Allergic reactions can range from mild skin reactions to severe systemic symptoms including angioedema, so it is essential to inform your healthcare provider of any previous adverse reactions to this or related medications.
Warnings and Precautions
Several important warnings apply to patients taking Epivir or other combination antiretroviral therapies. Your doctor should be informed if any of the following conditions apply to you, as they may require additional monitoring or dose adjustments:
- Hepatitis B co-infection: If you have hepatitis B in addition to HIV, do not stop taking Epivir without consulting your doctor. Abrupt discontinuation can cause a severe flare of hepatitis B, potentially resulting in liver decompensation and, in rare cases, liver failure. Your liver function should be closely monitored for several months after any change in treatment.
- Liver disease: Patients with pre-existing liver disease, including chronic hepatitis B or C, are at increased risk for hepatic adverse events during antiretroviral therapy. Regular monitoring of liver function tests is recommended.
- Obesity: Patients who are significantly overweight, particularly women, may be at increased risk for lactic acidosis and severe hepatomegaly with steatosis, a rare but potentially fatal complication associated with nucleoside analogues.
- Kidney disease: Lamivudine is primarily eliminated through the kidneys. Patients with renal impairment (creatinine clearance below 50 mL/min) require dose reduction. Your doctor will adjust the dosage based on your kidney function.
Immune Reconstitution Inflammatory Syndrome (IRIS)
Patients with advanced HIV infection (AIDS) who begin antiretroviral treatment may experience immune reconstitution inflammatory syndrome (IRIS). As the immune system recovers, it may mount an inflammatory response against previously dormant opportunistic infections, such as Mycobacterium avium complex, cytomegalovirus retinitis, Pneumocystis jirovecii pneumonia, or tuberculosis. These flare-ups typically occur within the first few weeks to months of starting treatment.
In addition to opportunistic infections, autoimmune disorders such as Graves' disease, polymyositis, and Guillain-Barré syndrome have been reported to occur after the initiation of antiretroviral therapy, sometimes many months after treatment begins. If you notice any new symptoms of infection, muscle weakness, heart palpitations, tremors, or hyperactivity after starting treatment, contact your doctor immediately.
Pregnancy and Breastfeeding
If you are pregnant, become pregnant, or are planning a pregnancy, discuss the risks and benefits of taking Epivir with your doctor. Lamivudine and similar nucleoside analogues may cause side effects in the developing foetus. However, the benefit of preventing mother-to-child transmission of HIV generally outweighs the potential risks, and lamivudine is included in WHO-recommended regimens for preventing vertical transmission.
If you have taken Epivir during pregnancy, your doctor may request regular blood tests and other diagnostic examinations to monitor your child's development. For children whose mothers have taken NRTIs during pregnancy, the benefit of HIV protection outweighs the risk of side effects.
Breastfeeding is not recommended for women living with HIV, as the virus can be transmitted to the infant through breast milk. Small amounts of the active ingredients in Epivir may also pass into breast milk. If you are breastfeeding or considering starting, discuss this with your doctor as soon as possible.
Driving and Operating Machinery
Epivir is unlikely to affect your ability to drive or operate machinery. However, individual responses to medication vary, and you should be aware of how you respond to the drug before engaging in activities that require alertness.
How Does Epivir Interact with Other Drugs?
Drug interactions can significantly affect the efficacy and safety of antiretroviral therapy. It is essential to inform your doctor or pharmacist of all medications you are currently taking, have recently taken, or plan to take, including prescription medicines, over-the-counter products, herbal remedies, and nutritional supplements. Always notify your doctor when starting any new medication while on Epivir.
Major Interactions (Avoid Combination)
| Drug / Substance | Interaction Type | Clinical Significance |
|---|---|---|
| Emtricitabine | Therapeutic duplication | Both are cytidine analogues with overlapping mechanisms. Combining them provides no additional benefit and increases toxicity risk. Never use together. |
| Other lamivudine products | Dose duplication | Avoid concurrent use of other products containing lamivudine (e.g. fixed-dose combinations such as Triumeq, Combivir, Trizivir, or Zeffix) to prevent overdose. |
| Cladribine | Pharmacodynamic antagonism | Used for hairy cell leukaemia. Lamivudine may reduce the intracellular phosphorylation and efficacy of cladribine. Avoid concomitant use. |
| Sorbitol and sugar alcohols | Reduced absorption | Regular use of products containing sorbitol, xylitol, mannitol, lactitol, or maltitol (often in liquid medications) can reduce lamivudine plasma levels by up to 40%. Avoid regular co-administration. |
Moderate Interactions (Use with Caution)
| Drug / Substance | Interaction Type | Clinical Significance |
|---|---|---|
| Co-trimoxazole (high dose) | Increased lamivudine levels | High-dose trimethoprim/sulfamethoxazole (used for Pneumocystis pneumonia treatment) increases lamivudine AUC by approximately 40% by inhibiting renal tubular secretion. Standard prophylactic doses do not require adjustment, but high therapeutic doses require monitoring. |
| Zalcitabine | Intracellular competition | Both drugs may compete for intracellular phosphorylation, potentially reducing the efficacy of one or both agents. Combination is generally not recommended. |
What Is the Correct Dosage of Epivir?
Always take Epivir exactly as your doctor or pharmacist has instructed. Do not change the dose without medical advice. Swallow the tablets whole with water. Epivir can be taken with or without food. If you cannot swallow the tablets whole, they may be crushed and mixed with a small amount of food or drink, but you must take the entire dose immediately.
Adults and Adolescents (≥25 kg)
Standard Adult Dose
The recommended dose is 300 mg daily, which can be administered as:
- One 150 mg tablet twice daily (approximately 12 hours apart), OR
- Two 150 mg tablets (300 mg) once daily
Your doctor will advise which dosing schedule is most appropriate for your treatment regimen.
Children
Dosing for children is based on body weight. The following weight-based dosing guidelines apply:
| Body Weight | Daily Dose | Dosing Schedule |
|---|---|---|
| ≥25 kg | 300 mg | 150 mg twice daily OR 300 mg once daily |
| 20 kg to <25 kg | 225 mg | 75 mg morning + 150 mg evening OR 225 mg once daily |
| 14 kg to <20 kg | 150 mg | 75 mg twice daily OR 150 mg once daily |
| <14 kg | Weight-based | Oral solution recommended (available for children ≥3 months) |
Kidney Impairment
Since lamivudine is primarily eliminated through the kidneys, dose reductions are necessary for patients with impaired renal function. Your doctor will determine the appropriate dose based on your creatinine clearance. An oral solution is available for patients who require doses lower than 150 mg. If you have any degree of kidney disease, discuss this with your doctor before starting or continuing treatment.
Missed Dose
If you forget to take a dose of Epivir, take it as soon as you remember. Then continue taking the medication as usual. Do not take a double dose to make up for a missed one. Consistent adherence to your antiretroviral regimen is crucial for maintaining viral suppression and preventing the development of drug resistance. If you frequently forget doses, discuss strategies for improving adherence with your doctor or pharmacist.
Overdose
If you accidentally take too much Epivir, contact your doctor, pharmacist, or the nearest emergency department immediately for further advice. If possible, show them the Epivir packaging. In clinical studies, no specific symptoms or signs have been identified following acute overdose with lamivudine, but standard supportive care should be provided. Lamivudine is dialysable, so continuous haemodialysis may be considered in cases of significant overdose, although this is rarely required.
What Are the Side Effects of Epivir?
Like all medicines, Epivir can cause side effects, although not everyone experiences them. During treatment of HIV infection, it is not always possible to distinguish between symptoms of the disease, side effects of Epivir, and side effects of other medications being taken at the same time. For this reason, it is very important to report all changes in your health to your doctor.
During HIV treatment, weight gain and increases in blood lipid and glucose levels may occur. This is partly related to restored health and lifestyle factors, but in some cases there may be a direct association with the antiretroviral medications. Your doctor will perform tests to monitor for these metabolic changes.
Common Side Effects
May affect up to 1 in 10 people
- Headache
- Nausea
- Vomiting
- Diarrhoea
- Abdominal (stomach) pain
- Fatigue, lack of energy
- Fever
- General feeling of being unwell (malaise)
- Muscle pain and discomfort
- Joint pain
- Difficulty sleeping (insomnia)
- Cough
- Irritated or runny nose
- Skin rash
- Hair loss (alopecia)
Uncommon Side Effects
May affect up to 1 in 100 people
- Decreased platelet count (thrombocytopaenia) – detected in blood tests
- Low red blood cell count (anaemia) – detected in blood tests
- Low white blood cell count (neutropaenia) – detected in blood tests
- Elevated liver enzyme levels – detected in blood tests
Rare Side Effects
May affect up to 1 in 1,000 people
- Severe allergic reaction (angioedema) causing swelling of the face, tongue, or throat, which can cause difficulty swallowing or breathing
- Inflammation of the pancreas (pancreatitis)
- Breakdown of muscle tissue (rhabdomyolysis)
- Liver inflammation (hepatitis)
- Elevated amylase levels – detected in blood tests
Very Rare Side Effects
May affect up to 1 in 10,000 people
- Lactic acidosis (excess lactic acid in the blood) – a potentially life-threatening condition
- Numbness and tingling in the arms, legs, hands, or feet (peripheral neuropathy)
- Pure red cell aplasia (failure of the bone marrow to produce new red blood cells) – detected in blood tests
Other Possible Effects of Combination HIV Treatment
Combination antiretroviral therapy, including regimens containing Epivir, may cause additional conditions to develop during treatment. These are related to the overall treatment approach rather than to lamivudine specifically.
Immune reconstitution inflammatory syndrome (IRIS): Patients with advanced HIV and a weakened immune system may experience inflammatory reactions to previously hidden infections when starting antiretroviral therapy. Additionally, autoimmune conditions including Graves' disease, polymyositis, and Guillain-Barré syndrome may develop months after beginning treatment. Seek medical advice immediately if you notice symptoms of infection, muscle weakness (particularly starting in the hands and feet), palpitations, tremors, or hyperactivity.
Osteonecrosis (bone death): Some patients on long-term combination antiretroviral therapy may develop osteonecrosis, a condition where bone tissue dies due to reduced blood supply. Risk factors include long duration of treatment, corticosteroid use, alcohol consumption, severe immunosuppression, and obesity. Symptoms include joint stiffness, aches and pains (especially in the hips, knees, or shoulders), and difficulty with movement. Contact your doctor if you experience any of these symptoms.
How Should You Store Epivir?
Proper storage of Epivir ensures that the medication remains effective and safe to use throughout its shelf life. The following storage guidelines should be observed:
- Store at a temperature not exceeding 30°C (86°F).
- Keep the medication in its original packaging to protect from moisture and light.
- Keep out of the sight and reach of children.
- Do not use Epivir after the expiry date stated on the carton or bottle. The expiry date refers to the last day of that month.
- Do not dispose of medications via wastewater or household waste. Ask your pharmacist how to dispose of medications that are no longer needed. These measures help protect the environment.
What Does Epivir Contain?
The active substance in Epivir is lamivudine. Each film-coated tablet contains either 150 mg or 100 mg of lamivudine.
The other ingredients (excipients) are:
- Tablet core: Microcrystalline cellulose, sodium starch glycolate (gluten-free), magnesium stearate
- Film coating: Hypromellose, titanium dioxide (E171), macrogol, polysorbate 80
Epivir 150 mg film-coated tablets are white, diamond-shaped, scored, and marked with "GXCJ7" on both sides. They are supplied in white polyethylene bottles or blister packs of 60 tablets. The scored tablet allows it to be divided into two equal halves when a 75 mg dose is required.
This medicine contains less than 1 mmol sodium (23 mg) per dosage unit, meaning it is essentially sodium-free.
Epivir is manufactured by Delpharm Poznań Spółka Akcyjna, Poland, and marketed by ViiV Healthcare BV, Netherlands. ViiV Healthcare is a specialist company dedicated to HIV treatment and research.
Frequently Asked Questions About Epivir
Epivir (lamivudine) is an antiretroviral medication used to treat HIV infection in adults and children. It belongs to the nucleoside reverse transcriptase inhibitor (NRTI) class and works by reducing the amount of HIV in the body while allowing the immune system to recover. It is always used as part of a combination antiretroviral treatment regimen, never as a single agent.
No, Epivir does not cure HIV. It is part of combination antiretroviral therapy (cART) that suppresses the virus to undetectable levels and allows the immune system to recover. Treatment must be taken consistently and lifelong. With effective treatment, people living with HIV can have near-normal life expectancy and an undetectable viral load, which also means the virus cannot be sexually transmitted (U=U: Undetectable = Untransmittable).
No. If you have hepatitis B co-infection, stopping Epivir abruptly can cause a severe flare-up of your hepatitis B, which may lead to serious liver damage. Always consult your doctor before making any changes to your treatment. If a change is necessary, your doctor will arrange close monitoring of your liver function for several months after the switch.
If you miss a dose, take it as soon as you remember and then continue your normal schedule. Do not take a double dose to compensate. Adherence is crucial for HIV treatment success and preventing drug resistance. If you frequently forget doses, speak with your doctor or pharmacist about strategies such as pill reminders, alarms, or simplified once-daily regimens.
Lamivudine has been used extensively in pregnancy as part of regimens to prevent mother-to-child HIV transmission. While nucleoside analogues can potentially cause side effects in the foetus, the benefit of preventing HIV transmission to the baby generally outweighs the risks. Lamivudine is included in WHO-recommended first-line regimens for pregnant women living with HIV. Discuss the specific risks and benefits with your doctor.
The most serious but rare side effects include lactic acidosis (a dangerous build-up of lactic acid in the blood), pancreatitis (inflammation of the pancreas), severe allergic reactions with facial swelling, and hepatitis. Symptoms that require immediate medical attention include persistent nausea, vomiting, abdominal pain, rapid breathing, unusual muscle pain, swelling of the face or throat, and yellowing of the skin or eyes.
References
- World Health Organization (WHO). Consolidated guidelines on HIV prevention, testing, treatment, service delivery and monitoring: recommendations for a public health approach. Geneva: WHO; 2021.
- European AIDS Clinical Society (EACS). EACS Guidelines Version 12.0. October 2023. Available at: eacs.sanfordguide.com
- Panel on Antiretroviral Guidelines for Adults and Adolescents. Guidelines for the use of antiretroviral agents in adults and adolescents with HIV. Department of Health and Human Services (DHHS). Updated 2024.
- British HIV Association (BHIVA). BHIVA guidelines for the treatment of HIV-1-positive adults with antiretroviral therapy. HIV Medicine. 2022;23(Suppl 5):1-115.
- European Medicines Agency (EMA). Epivir – Summary of Product Characteristics. Last updated 2024.
- Wainberg MA. The impact of the M184V substitution on drug resistance and viral fitness. Expert Rev Anti Infect Ther. 2004;2(1):147-151.
- GlaxoSmithKline/ViiV Healthcare. Epivir (lamivudine) Prescribing Information. U.S. Food and Drug Administration. Revised 2023.
- World Health Organization (WHO). WHO Model List of Essential Medicines – 23rd List. Geneva: WHO; 2023. Lamivudine listed as an essential antiretroviral.
Editorial Team
This article was written and reviewed by our medical editorial team, consisting of licensed physicians specialising in infectious disease, clinical pharmacology, and internal medicine.
Medical Content Team
Specialist physicians in infectious disease and clinical pharmacology with expertise in HIV/AIDS treatment and antiretroviral therapy.
Medical Review Board
Independent panel following WHO, EACS, DHHS, and BHIVA guidelines. GRADE evidence framework applied to all clinical recommendations.
Conflict of Interest Statement: The iMedic editorial team operates independently with no pharmaceutical industry funding or commercial sponsorship. All content is based on current evidence-based guidelines and peer-reviewed literature.