Lamivudine
Pronunciation: la-MIV-yoo-deen.
- Generic name
- lamivudine
- Brand names
- Epivir (HIV formulation, United States), Epivir-HBV (hepatitis B formulation, United States)
- Drug class
- Nucleoside reverse transcriptase inhibitor (NRTI)
- Form
- Tablet or oral solution
- Route
- Oral
- Legal status
- Prescription-only medicine.
Availability and supply rules vary by country
Trade names by country: United States · Canada
Australia: · Full directory
Boxed warning: Lactic acidosis, liver problems, and hepatitis flare-ups after stopping
Lactic acidosis and severe liver enlargement with fatty liver (hepatomegaly with steatosis), including fatal cases, have been reported with lamivudine and similar medicines. Treatment must be evaluated urgently if these are suspected. Separately, in people with both HIV and hepatitis B who stop taking lamivudine, severe flare-ups of hepatitis have occurred; anyone stopping this medicine while also having hepatitis B needs close liver monitoring for several months afterward, arranged by their treating clinician. Epivir (for HIV) and Epivir-HBV (for hepatitis B) contain different lamivudine doses and must never be substituted for one another. (1)
What lamivudine is and how it works
Lamivudine is an antiviral medicine (a nucleoside reverse transcriptase inhibitor) used as part of combination treatment for HIV-1 infection. (1)
It is always used together with other antiretroviral medicines for HIV, never alone. A separate, lower-dose version of lamivudine is used for chronic hepatitis B; these two uses are not interchangeable, and a person with HIV must always receive the HIV-appropriate product and dose.
Mechanism of action: how lamivudine works
Lamivudine is a cytosine nucleoside analogue that is phosphorylated intracellularly to its active triphosphate form, which inhibits HIV reverse transcriptase by competing with the natural substrate and causing DNA chain termination. (1)
What lamivudine is used for
HIV-1 infection (combination therapy)
Used together with other antiretroviral medicines to treat HIV-1 infection. It is not used as the only medicine for HIV. (1)
Before taking lamivudine
Do not take / not appropriate for
- Do not take lamivudine if you have had a significant hypersensitivity reaction, including anaphylaxis, to lamivudine or a product ingredient. (all products) (1)
Tell your clinician about
- Whether you have hepatitis B in addition to HIV, since stopping lamivudine can trigger a serious flare of hepatitis B in this situation and needs planned monitoring.
- Kidney function, since the dose is adjusted for reduced kidney function.
- Any history of pancreatitis, especially in children.
- Every other medicine you take, and never combine this with another lamivudine-containing product or with zalcitabine.
- Pregnancy, plans for pregnancy, or breastfeeding.
How to take lamivudine
- Take exactly as prescribed, always as part of a complete HIV treatment combination.
- Do not change your dose, or stop taking lamivudine, without your prescriber's direct involvement and a monitoring plan, especially if you also have hepatitis B.
- Never use a hepatitis-B-only lamivudine product in place of your prescribed HIV product, or vice versa.
Procedures and treatment changes
Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1)
Missed dose
Follow the instructions from your HIV care team for a missed dose, since missed doses can affect how well your treatment combination works. Do not take a double dose to make up for a missed one.
Overdose
Contact your prescriber, pharmacist, or a poison-control/emergency service if an overdose is suspected.
Side effects
Common effects are usually mild, but some effects, especially on the liver, pancreas, or muscles, need prompt medical evaluation.
Headache, nausea, tiredness, or nasal symptoms
What to notice: Commonly reported effects.
What to do: Tell your HIV care team if severe or persistent. (1)
Diarrhoea or cough
What to notice: Commonly reported effects.
What to do: Tell your care team if troublesome. (1)
Changes in body fat distribution
What to notice: Fat loss from the face or limbs, or fat gain around the abdomen or upper back, can occur with long-term antiretroviral therapy.
What to do: Discuss any noticeable changes with your care team. (1)
Signs of lactic acidosis or liver problems
What to notice: Unusual muscle pain or weakness, trouble breathing, stomach pain with nausea and vomiting, feeling cold especially in the arms and legs, dizziness, or a fast or irregular heartbeat.
What to do: Seek urgent medical evaluation; a clinician will decide whether lamivudine needs to be stopped and how to monitor you afterward. (1)
New inflammatory symptoms after starting treatment
What to notice: New fever, swollen glands, or other new symptoms in the weeks after starting combination HIV therapy.
What to do: Contact your HIV care team promptly; this can reflect the immune system reacting to a previously hidden infection as it recovers. (1)
Serious warnings
Lactic acidosis and severe liver problems — emergency
Symptoms: Unusual muscle pain, trouble breathing, stomach pain with nausea and vomiting, feeling unusually cold, dizziness, or irregular heartbeat.
Action: Seek emergency medical care immediately; fatal cases have been reported. A clinician will urgently evaluate and decide whether lamivudine needs to be stopped. (1)
Hepatitis B flare after stopping lamivudine (in people with HIV and hepatitis B together) — emergency
Symptoms: Worsening jaundice, abdominal pain, or feeling very unwell after lamivudine has been stopped or changed.
Action: This is a recognised, serious risk specifically after stopping lamivudine in people with both HIV and hepatitis B. Any decision to stop or change this medicine must be made and closely monitored by your clinician, with liver monitoring continuing for several months afterward; do not stop on your own. (1)
Pancreatitis — urgent
Symptoms: Severe abdominal pain, often with nausea and vomiting.
Action: Seek prompt medical attention; this risk is higher in children who have previously taken similar antiviral medicines. (1)
Severe allergic reaction — emergency
Symptoms: Swelling of the face, lips, tongue, or throat, or difficulty breathing.
Action: Seek emergency medical help immediately. (1)
Interactions
| Medicine or test | Effect | Action |
|---|---|---|
| Other lamivudine-containing products or emtricitabine | These should never be combined with this medicine, as they contain the same or a very similar active ingredient. | Tell every prescriber and pharmacist exactly which HIV medicines you take. (1) |
| Zalcitabine | Lamivudine can inhibit the activation of zalcitabine inside cells, reducing its effect. | This combination is not recommended. (1) |
| Trimethoprim/sulfamethoxazole | Increases lamivudine blood levels, though no dose adjustment is generally needed. | Tell your care team if you are prescribed this antibiotic combination. (1) |
| Interferon and ribavirin (in people also treated for hepatitis C) | Hepatic decompensation, sometimes fatal, has been reported in coinfected patients on this combination, though no direct pharmacokinetic interaction was found. | This combination requires close specialist monitoring. (1) |
Pregnancy, breastfeeding, kidney/liver function, age
HIV and hepatitis B coinfection
Stopping lamivudine in this situation carries a real risk of a serious hepatitis flare. Any change to this medicine must be planned and monitored by your clinician, including liver monitoring for several months after stopping. (1)
Kidney impairment
The dose is reduced according to kidney function (creatinine clearance); your prescriber will set the correct dose and interval. (1)
Pregnancy
Lamivudine crosses the placenta. Exposure during pregnancy can be recorded in the Antiretroviral Pregnancy Registry. Discuss the benefits and risks with your care team. (1)
Breastfeeding
Current guidance recommends that mothers with HIV do not breastfeed, due to the risk of transmitting HIV to the infant, regardless of lamivudine levels in breast milk. (1)
Children
Weight-based dosing is used in children; pancreatitis risk may be higher in children previously treated with similar antiviral medicines. (1)
Monitoring
Before starting
- Confirm HIV status and the full combination regimen being used.
- Test for hepatitis B coinfection, since this changes the risk profile of stopping treatment later.
- Assess kidney function to set the correct dose.
- Review history of pancreatitis, especially in children.
During treatment
- Watch for signs of lactic acidosis or liver problems.
- If hepatitis B coinfected, plan for close liver monitoring for several months if lamivudine is ever stopped or changed.
- Watch for new inflammatory symptoms in the weeks after starting combination therapy (immune reconstitution).
- Never substitute between HIV and hepatitis-B-only lamivudine products.
Storage
Store as directed on the product label, out of reach of children.
Professional information
Clinician-facing context only. Use the current local product information for exact dosing and hepatitis B coinfection management.
United States
Indication: HIV-1, combination therapy
Dose summary: Adults/adolescents over 16 years: 300 mg/day as 150 mg twice daily or 300 mg once daily. Pediatric (3 months-16 years): 4 mg/kg twice daily oral solution, maximum 150 mg twice daily.
Renal context: Dose reduced according to creatinine clearance: 150 mg twice daily if CrCl 50 mL/min or above, down to 50 mg first dose then 25 mg daily if CrCl under 5 mL/min. Hemodialysis removes negligible amounts; no supplemental post-dialysis dose needed. (1)
Hepatic guidance
Suspend treatment for clinical or laboratory evidence of lactic acidosis or pronounced hepatotoxicity; monitor hepatic function closely for several months after discontinuation in HIV/HBV-coinfected patients.
Overdose note
No specific antidote is described in the source reviewed; manage supportively per local toxicology guidance. (1)
Frequently asked questions
What is lamivudine used for?
lamivudine is prescribed for approved indications. Always follow your healthcare provider's guidance.
What are the side effects of lamivudine?
Common side effects may include gastrointestinal symptoms and headache. Serious side effects require immediate medical attention.
Can I take lamivudine with other medications?
Always inform your healthcare provider about all medications you are taking, including over-the-counter products and supplements.
What is the mechanism of action of lamivudine?
Lamivudine is a cytosine nucleoside analogue that is phosphorylated intracellularly to its active triphosphate form, which inhibits HIV reverse transcriptase by competing with the natural substrate and causing DNA chain termination. (1)
What is the generic name of Lamivudine?
The generic name is lamivudine. It is sold under brand names including Epivir (HIV formulation, United States), Epivir-HBV (hepatitis B formulation, United States). (1)
What class of drug is lamivudine?
Lamivudine is classed as: Nucleoside reverse transcriptase inhibitor (NRTI). (1)
References
- EPIVIR (lamivudine) tablet, film coated — prescribing information (boxed warning)DailyMed, U.S. National Library of Medicine (FDA-approved label) · United States · accessed 2026-07-26 · source 1
- LAMIVUDINE TABLET, FILM COATED [CAMBER PHARMACEUTICALS, INC.] — US prescribing information (DailyMed SPL)U.S. National Library of Medicine (DailyMed) · US · accessed 2026-08-14 · source 2
- Lamivudine — patient drug information (MedlinePlus)U.S. National Library of Medicine (MedlinePlus) · US · accessed 2026-08-14 · source 3
- LAMIVUDINE and ZIDOVUDINE — FDA approval record (Drugs@FDA ANDA079124)U.S. Food and Drug Administration · US · accessed 2026-08-14 · source 4
- lamivudine — RxNorm normalized drug concept (RXCUI 68244)U.S. National Library of Medicine (RxNorm) · US · accessed 2026-08-14 · source 5
Brand names by country
Single-ingredient lamivudine names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.
Priority countries
United States
- EPIVIR300 mg, 10 mg/mL, 150 mg · viiv healthcare company
Canada
- HEPTOVIR
- APO-LAMIVUDINE HBV