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Tablets containing 100 mg of lamivudine.

Drugs List

  • lamivudine 100mg tablets
  • ZEFFIX 100mg tablets
  • Therapeutic Indications


    Hepatitis B - chronic active

    Lamivudine is indicated for the treatment of chronic hepatitis B in adults with:
    Compensated hepatic disease with evidence of active viral replication, persistently elevated serum alanine aminotransferase (ALT) levels and histological evidence of active liver inflammation and/or fibrosis. Only consider when use of alternative antiviral with a higher genetic barrier is not appropriate.
    Decompensated hepatic disease in combination with second agent.


    Therapy should be initiated by a physician experienced in the treatment of chronic hepatitis B.


    100mg once daily.

    In patients treated with decompensated hepatic disease, lamivudine should be used in combination with another agent without cross-resistance to lamivudine in order to reduce the risk of resistance and to achieve rapid viral suppression.

    Duration of treatment varies for individual patients, optimal duration is unknown. If treatment is discontinued, patients should be periodically monitored for evidence of recurrent hepatitis.

    Patients with HBeAg positive chronic hepatitis B (CHB) without cirrhosis
    Treatment should be administered for at least six to twelve months after HBeAg seroconversion (HBeAg and HBV DNA loss with HBeAb detection) is confirmed, to limit the risk of virological relapse, or until HBsAg seroconversion or there is loss of efficacy. Serum ALT and HBV DNA levels should be followed regularly after treatment discontinuation to detect any late virological relapse.

    Patients with HBeAg negative CHB (pre-core mutant) without cirrhosis
    Treatment should be administered at least until HBs seroconversion or there is evidence of loss of efficacy. With prolonged treatment, regular reassessment is recommended to confirm that continuation of the selected therapy remains appropriate for the patient.

    HBeAg positive or HBeAg negative patients
    The development of tyrosine-methionine-aspartate-aspartate (YMDD) mutant HBV may result in a diminished therapeutic response to lamivudine. This diminished response is indicated by a rise in HBV DNA and ALT from previous on-treatment levels. In order to reduce the risk of resistance in patients receiving lamivudine monotherapy, a modification of treatment, either by switching to an alternative agent or by adding an alternative agent without cross-resistance to lamivudine, should be considered if serum HBV DNA remains detectable at or beyond twenty four weeks of treatment.

    In patients with YMDD variant HBV, an additional agent without lamivudine cross-resistance should be considered.

    Patients with decompensated hepatic disease or cirrhosis and in liver transplant recipients
    Treatment cessation is not recommended. If there is a loss of efficacy due to the YMDD variant HBV emerging in these patients, additional or alternative therapies should be considered.


    Children aged 12 to 18 years (unlicensed)
    100mg once daily.

    Children aged 2 to 12 years (unlicensed)
    3mg/kg once daily (up to 100mg daily).

    Patients with Renal Impairment

    Lamivudine serum concentrations are increased in patients with moderate to severe renal impairment.

    The dosage should be reduced for patients with a creatinine clearance of less than 50 ml/minute.

    Creatinine clearance 30 to less than 50ml/minute
    First dose of 100mg. Maintenance dose of 50mg once daily.

    Creatinine clearance 15 to less than 30ml/minute
    First dose of 100mg. Maintenance dose of 25mg once daily.

    Creatinine clearance 5 to less than 15ml/minute
    First dose of 35mg. Maintenance dose of 15mg once daily.

    Creatinine clearance less 5ml/minute
    First dose of 35mg. Maintenance dose of 10mg once daily.

    Patients undergoing intermittent haemodialysis
    At the time of writing, available data indicate that following the initial dosage reduction of lamivudine to correct for the patient's creatinine clearance, no further dosage adjustments are required while undergoing dialysis.

    Additional Dosage Information

    Patients co-infected with HIV
    Other lamivudine formulations are indicated for HIV, see relevant monograph and product details for more information. For the treatment of patients co-infected with HIV and are currently receiving or about to receive treatment with a lamivudine containing regime, the dose of lamivudine prescribed should be maintained.

    For HIV co-infected patients who do not require antiretroviral therapy, there is a risk of HIV mutation when using lamivudine alone for treating chronic hepatitis B.


    Children under 2 years

    Precautions and Warnings

    Children aged 2 to 18 years
    Liver transplant
    Positive HIV status
    Renal impairment - creatinine clearance below 50ml/minute

    Reduce dose in patients with creatinine clearance below 50ml/min
    Therapy cessation not recommended in decompensated liver disease/cirrhosis
    Treatment does not prevent risk of transmission of Hepatitis B
    Treatment to be initiated and supervised by a specialist
    Autoimmune disorders can occur many months after initiation of treatment
    Monitor patient for some months after discontinuing treatment
    Monitor viral markers frequently
    On discontinuation, may cause recurrence of hepatitis B
    Perform liver function tests every 3 months
    Neonate exposed in utero: Risk of mitochondrial dysfunction

    Other lamivudine formulations are indicated for HIV, see relevant monograph and product details for more information.

    Patients should be monitored regularly, including ALT levels monitored every 3 months and HBV DNA and HBeAg levels determined every 6 months.

    Data is limited on the use of lamivudine in pre-core mutant (HBeAg negative) patients and those receiving concurrent immunosuppressive agents, including cancer chemotherapy. Therefore, caution is advised.

    Exacerbations in chronic hepatitis B are characterised by transient increases in serum ALT and re-emergence of HBV DNA. In patients with compensated liver disease, these increases in serum ALT were not generally accompanied by an increase in serum bilirubin or signs of hepatic decompensation.

    Hepatitis B viral subpopulations with reduced susceptibility to lamivudine (YMDD variant HBV) may develop with extended therapy. In some patients the development of YMDD variant HBV can lead to exacerbation of hepatitis. In patients with YMDD variant HBV, a switch to or addition of a second agent without lamivudine cross resistance should be considered.

    If lamivudine is discontinued a recurrence of hepatitis may occur in some patients. After discontinuation, patients should be periodically monitored clinically and by assessment of serum liver function tests (ALT and bilirubin levels) for at least four months after discontinuation and as clinically indicated thereafter.

    There is a greater risk of active viral replication in transplantation recipients and patients with advanced liver disease. The recurrence of hepatitis after discontinuation or when efficacy of lamivudine is reduced in these patients can lead to severe and even fatal decompensation. These patients should be monitored at least every month during treatment, with tests to determine clinical, virological and serological parameters associated with hepatitis B, renal and hepatic function, and antiviral response. If lamivudine is discontinued, these tests should continue for at least 6 months after treatment cessation. Laboratory parameters to be monitored should include at least, serum ALT, bilirubin, albumin, blood urea nitrogen, creatinine, virological status, HBV antigen/antibody, and serum HBV DNA concentrations. Patients experiencing signs of hepatic impairment during or after treatment should be monitored more frequently.
    If recurrent hepatitis occurs, there is insufficient data on the reintroduction of lamivudine therapy.

    Treatment regimens containing nucleoside or nucleotide analogues have been reported to cause mitochondrial dysfunction in HIV-negative infants exposed in utero and/or post-natally. Adverse reactions such as haematological (anaemia, neutropenia), metabolic (hyperlactataemia, hyperlipasemia) and neurological (hypertonia, convulsions, abnormal behaviour) have been reported. Consider in children exposed to nucleoside or nucleotide analogues in utero (including HIV-negative infants) and who present with neurological symptoms or severe clinical findings of unknown cause.

    Pregnancy and Lactation


    Use lamivudine with caution in pregnancy.

    Briggs suggests if indicated, lamivudine should not be withheld because of pregnancy. The manufacturer suggests lamivudine can be used in pregnancy if clinically indicated.

    Animal studies in rabbits have shown an increase in early embryonic deaths however this was not seen in rats. No teratogenic effects were observed in rats and rabbits administered up to 130 and 60 times the usual adult dose.

    More than 1000 pregnancies exposed to lamivudine did not indicate malformative toxicity. Lamivudine crosses the placenta and foetal levels have been found to be similar to or higher than the maternal levels.
    Animal and human data suggest low risk to the developing foetus for structural malformations. Impaired fertility as a result of embryonic cytotoxicity could occur with but this has not been studied in humans.

    Mitochondrial dysfunction in neonates following in utero exposure to treatment regimens containing nucleoside and nucleotide analogue has been reported. It is unknown whether there are any long term consequences of in utero and infant exposure to lamivudine. Consider in children exposed to nucleoside or nucleotide analogues in utero (including HIV-negative infants) and who present with neurological symptoms or severe clinical findings of unknown cause.

    Patients co-infected with hepatitis who become pregnant and withdraw lamivudine may have a re-occurrence of hepatitis.

    The use of all medication in pregnancy should be avoided whenever possible; particularly in the first trimester. Non-drug treatments should also be considered. When essential, a medication with the best safety record over time should be chosen, employing the lowest effective dose for the shortest possible time. Polypharmacy should be avoided. Teratogens taken in the pre-embryonic period, often quoted as lasting until 14 to 17 days post-conception, are believed to have an all-or-nothing effect. Where drugs have a short half-life, and when the date of conception is certain, this may allow women to be reassured where drug exposure has occurred within this time frame. Further advice may be available from the UK National Teratology Information Service (NTIS) and through ToxBase, available via password on the internet ( ) or if this is unavailable at the backup site ( ).


    Use lamivudine with caution in breastfeeding.

    The manufacturer suggests breastfeeding may be considered in patients being treated for hepatitis B taking into account the benefit of breastfeeding for the child and the benefit of therapy for the woman. Where there is maternal transmission of hepatitis B, despite adequate prophylaxis, consider discontinuing breastfeeding to reduce of lamivudine resistant mutants in the infant. Maternal hepatitis B is not a contraindication to breastfeeding if the child is adequately managed for hepatitis B prevention at birth.

    Lamivudine is excreted into breast milk. Based on more than 200 mother and child pairs treated for HIV, serum concentrations of lamivudine in breastfed infants of treated mothers were low (less than 4% of maternal serum concentrations) and progressively decreased to undetectable levels when infants reached 24 weeks old. The low levels ingested by the infant are likely to result in sub-optimal antiviral effect. At the time of writing there are no evidence that the low concentrations in human milk leads to adverse reactions in the breastfed infant.

    Neonates, infants born prematurely, those with low birth weight, those with an unstable gastrointestinal function or who have serious illnesses may require special consideration. For any infant, if a drug is prescribed to the nursing mother, it should be at the lowest practical dose and for the shortest time. When drug administration is unavoidable and breastfeeding is to continue, minimisation of exposure of the infant to the drug may sometimes be achieved by timing the maternal doses to just after a feeding episode. Infants exposed to drugs via breast milk should be monitored for unusual signs or symptoms. Interactions between the drug received by the infant from the mother's milk and medication prescribed for the infant should also be considered, for example, when the drug given to the infant may prevent metabolism of the drug received via breast milk.
    Specialist advice is available from the UK Drugs in Lactation Advisory Service at

    Side Effects

    Abdominal discomfort
    Abdominal pain
    Autoimmune hepatitis
    Creatine phosphokinase increased
    Exacerbation of hepatitis
    Graves' disease
    Hepatic steatosis
    Increase in ALT level
    Lactic acidosis
    Muscle disorders
    Muscular cramps
    Nasal symptoms
    Peripheral neuropathy
    Respiratory tract infection
    Severe hepatomegaly
    Throat discomfort


    It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.

    The following number will direct the caller to the relevant local centre (0844) 892 0111

    Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( ) or if this is unavailable at the backup site ( ).

    Further Information

    Last Full Review Date: February 2016

    Reference Sources

    Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 2nd edition (2007) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.

    Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 9th edition (2011) ed. Briggs, G., Freeman, R. and Yaffe, S. Lippincott Williams & Wilkins, Philadelphia.

    Medications and Mothers' Milk, Sixteenth Edition (2014) Hale, T and Rowe, H, Hale Publishing, Plano, Texas.

    Summary of Product Characteristics: Zeffix 100 mg film-coated tablets. GlaxoSmithKline UK. Revised November 2018.

    NICE Evidence Services Available at: Last accessed: 12 September 2017

    US National Library of Medicine. Toxicology Data Network. Drugs and Lactation Database (LactMed).
    Available at:
    Lamivudine Last revised: 10 March, 2015.
    Last accessed: 18 February, 2016.

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