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Nucleoside reverse transcriptase inhibitor Pregnancy: §4.6, verbatim: 'As a general rule, when deciding to use antiretroviral agents for the treatment of HIV infection in pregnant women and consequently for reducing the risk of HIV vertical transmission to the newborn, the animal data as well as the clinical experience in pregnant women should be taken into account. Animal studies with lamivudine showed an increase in early embryonic deaths in rabbits but not in rats. Placental transfer of lamivudine has been shown to occur in humans. More than 1000 outcomes from first trimester and more than 1000 outcomes from second and third trimester exposure in pregnant women indicate no malformative and foeto/neonatal effect. Epivir can be used during pregnancy if clinically needed. The malformative risk is unlikely in humans based on those data. For patients co-infected with hepatitis who are being treated with lamivudine and subsequently become pregnant, consideration should be given to the possibility of a recurrence of hepatitis on discontinuation of lamivudine.' BREAST-FEEDING: 'Following oral administration lamivudine was excreted in breast milk at similar concentrations to those found in serum. Based on more than 200 mother/child pairs treated for HIV, serum concentrations of lamivudine in breastfed infants of mothers treated for HIV are very low (< 4% of maternal serum concentrations)... There are no data available on the safety of lamivudine when administered to babies less than three months old. It is recommended that women living with HIV do not breast-feed their infants in order to avoid transmission of HIV.' FERTILITY: 'Studies in animals showed that lamivudine had no effect on fertility.'

Lamivudine

Brand names: Epivir, Zeffix

Lamivudine is a nucleoside reverse transcriptase inhibitor used as part of combination antiretroviral therapy for HIV infection and for the treatment of chronic hepatitis B.

Adult dose

Dose: HIV — adults, adolescents and children weighing at least 25 kg: 300 mg daily, given as either 150 mg twice daily or 300 mg once daily.
Route: Oral — 300 mg film-coated tablets, with or without food. 'To ensure administration of the entire dose, the tablet(s) should ideally be swallowed without crushing'; for patients unable to swallow tablets, 'the tablet(s) may be crushed and added to a small amount of semi-solid food or liquid, all of which should be consumed immediately', or a 10 mg/mL oral solution is available.
Frequency: Once daily (300 mg) or twice daily (150 mg). 'The 300 mg tablet is only suitable for the once a day regimen.'
Max: Maximum 300 mg daily for HIV in adults, adolescents and children weighing at least 25 kg — this is the highest dose stated anywhere in the fetched SPC (§4.2, verbatim: 'The recommended dose of Epivir is 300 mg daily. This may be administered as either 150 mg twice daily or 300 mg once daily'). NOTE: the SPC does not itself use the word 'maximum', and the dose must be REDUCED below this whenever creatinine clearance is under 50 ml/min — see renalAdjustment.
SCOPE STATEMENT: this covers the page's PRIMARY indication only — HIV-1 (Epivir). Chronic hepatitis B is NOT sourced: no HBV lamivudine product is present in this bundle, so no HBV dose is published. || SPECIALIST INITIATION (§4.2, verbatim): 'The therapy should be initiated by a physician experienced in the management of HIV infection.' || NOT FOR MONOTHERAPY (§4.4, verbatim): 'Epivir is not recommended for use as monotherapy.' || SWITCHING BETWEEN REGIMENS (§4.2, verbatim): 'Patients changing from the twice daily dosing regimen to the once daily dosing regimen should take the recommended once daily dose (as described above) approximately 12 hours after the last twice daily dose, and then continue to take the recommended once daily dose (as described above) approximately every 24 hours. When changing back to a twice daily regimen, patients should take the recommended twice daily dose approximately 24 hours after the last once daily dose.' || FORMULATION SWITCHING (§4.2): 'Patients changing between lamivudine oral solution and lamivudine tablets should follow the dosing recommendations that are specific for the formulation.' || OLDER PEOPLE (§4.2, verbatim): 'No specific data are available; however, special care is advised in this age group due to age-associated changes such as the decrease in renal function and alteration of haematological parameters.'

Paediatric dose

Route: Oral (150 mg scored tablets, or 10 mg/mL oral solution)
Frequency: Once daily, or as two divided doses daily
Max: Maximum 300 mg daily — children weighing at least 25 kg take the same dose as adults and adolescents (300 mg daily); no higher paediatric dose appears anywhere in the fetched SPC.
Concentration: 10 mg/ml
dosePerKg is deliberately null: the SPC's paediatric HIV dosing is by WEIGHT BAND, not per kilogram, so no single per-dose mg-per-kg figure is valid across the paediatric range. Verbatim (§4.2, 'Children (weighing less than 25 kg): Dosing according to weight bands is recommended for Epivir tablets'): 'Children weighing ≥ 20 kg to <25 kg: The recommended dose is 225 mg daily. This may be administered as either 75 mg (one-half of a 150 mg tablet) taken in the morning and 150 mg (one whole 150 mg tablet) taken in the evening, or 225 mg (one and a half 150 mg tablets) taken once daily. Children weighing 14 to < 20 kg: The recommended dose is 150 mg daily. This may be administered as 75 mg (one-half of a 150 mg tablet) taken twice daily, or 150 mg (one whole 150 mg tablet) taken once daily.' Children weighing at least 25 kg take the adult dose of 300 mg daily. || FORMULATION (§4.2): 'Children from three months of age: As an accurate dosage cannot be achieved with the 300 mg non-scored tablet formulation in this patient population, it is recommended that the Epivir 150 mg scored tablet formulation is used'; and 'Epivir is also available as an oral solution for children over three months of age and who weigh less than 14 kg or for patients who are unable to swallow tablets'. The concentration field above (10 mg per mL) is the SPC's stated oral-solution strength: 'The Epivir 10 mg/mL oral solution'. || AGE FLOOR (§4.2, verbatim): 'Children less than three months of age: The limited data available are insufficient to propose specific dosage recommendations.' || THE ONLY PER-KILOGRAM PAEDIATRIC FIGURES IN THIS SPC SIT INSIDE THE RENAL-IMPAIRMENT TABLE for children aged at least 3 months and weighing less than 25 kg, and are therefore not published as a general dose: creatinine clearance ≥50 ml/min — first dose 10 mg/kg or 5 mg/kg, maintenance 10 mg/kg once daily or 5 mg/kg twice daily; 30 to <50 — first dose 5 mg/kg, maintenance 5 mg/kg once daily; 15 to <30 — first dose 5 mg/kg, maintenance 3.3 mg/kg once daily; 5 to <15 — first dose 5 mg/kg, maintenance 1.6 mg/kg once daily; <5 — first dose 1.6 mg/kg, maintenance 0.9 mg/kg once daily. || PAEDIATRIC SAFETY (§4.8): 1206 HIV-infected paediatric patients aged 3 months to 17 years were enrolled in the ARROW trial, 669 of whom received abacavir and lamivudine either once or twice daily; 'No additional safety issues have been identified in paediatric subjects receiving either once or twice daily dosing compared to adults.' || Paediatric dosing must be checked against a current children's formulary before prescribing.

Dose adjustments

Renal

MANDATORY. §4.2, verbatim: 'Lamivudine concentrations are increased in patients with moderate - severe renal impairment due to decreased clearance. The dose should therefore be adjusted, using oral solution presentation of Epivir for patients whose creatinine clearance falls below 30 ml/min.' ADULTS, ADOLESCENTS AND CHILDREN WEIGHING AT LEAST 25 KG (creatinine clearance ml/min — first dose — maintenance dose): ≥50 — 300 mg or 150 mg — 300 mg once daily or 150 mg twice daily; 30 to <50 — 150 mg — 150 mg once daily; <30 — 'As doses below 150 mg are needed the use of the oral solution is recommended'; 15 to <30 — 150 mg — 100 mg once daily; 5 to <15 — 150 mg — 50 mg once daily; <5 — 50 mg — 25 mg once daily. CHILDREN aged at least 3 months and weighing less than 25 kg (creatinine clearance ml/min — first dose — maintenance dose): ≥50 — 10 mg/kg or 5 mg/kg — 10 mg/kg once daily or 5 mg/kg twice daily; 30 to <50 — 5 mg/kg — 5 mg/kg once daily; 15 to <30 — 5 mg/kg — 3.3 mg/kg once daily; 5 to <15 — 5 mg/kg — 1.6 mg/kg once daily; <5 — 1.6 mg/kg — 0.9 mg/kg once daily. The SPC adds: 'There are no data available on the use of lamivudine in children with renal impairment. Based on the assumption that creatinine clearance and lamivudine clearance are correlated similarly in children as in adults; it is recommended that the dosage in children with renal impairment be reduced according to their creatinine clearance by the same proportion as in adults. The Epivir 10 mg/mL oral solution may be the most appropriate formulation to achieve the recommended dose in children with renal impairment aged at least 3 months and weighing less than 25kg.'

Hepatic

§4.2, verbatim: 'Data obtained in patients with moderate to severe hepatic impairment shows that lamivudine pharmacokinetics are not significantly affected by hepatic dysfunction. Based on these data, no dose adjustment is necessary in patients with moderate or severe hepatic impairment unless accompanied by renal impairment.'

Dose independently re-sourced from UK Summary of Product Characteristics (SPC) via the eMC — clinician-reviewed. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Hypersensitivity to the active substance or to any of the excipients (§4.3, verbatim: 'Hypersensitivity to the active substance or to any of the excipients listed in section 6.1.') — this is the ONLY contraindication in the fetched SPC
  • Not a contraindication but a stated restriction (§4.4, verbatim): 'Epivir is not recommended for use as monotherapy.'
  • Not a contraindication but a stated restriction (§4.2, verbatim): 'Children less than three months of age: The limited data available are insufficient to propose specific dosage recommendations.'
  • Not a contraindication but a combination warning (§4.4, verbatim): 'There have been reports of a high rate of virological failure and of emergence of resistance at an early stage when lamivudine was combined with tenofovir disoproxil fumarate and abacavir as well as with tenofovir disoproxil fumarate and didanosine as a once daily regimen.'
  • Not a contraindication but a stop rule (§4.4, verbatim): 'Treatment with Epivir should be stopped immediately if clinical signs, symptoms or laboratory abnormalities suggestive of pancreatitis occur.'

Side effects

  • Common (§4.8): headache, insomnia; cough, nasal symptoms; nausea, vomiting, abdominal pain or cramps, diarrhoea; rash, alopecia; arthralgia, muscle disorders; fatigue, malaise, fever
  • Uncommon (§4.8): neutropenia and anaemia (both occasionally severe), thrombocytopenia; transient elevations in liver enzymes (AST, ALT)
  • Rare (§4.8): pancreatitis, elevations in serum amylase; hepatitis; angioedema; rhabdomyolysis
  • Very rare (§4.8): pure red cell aplasia; lactic acidosis; peripheral neuropathy (or paraesthesia)
  • Metabolic (§4.8/§4.4): 'Weight and levels of blood lipids and glucose may increase during antiretroviral therapy'
  • Immune reconstitution (§4.8): in patients with severe immune deficiency at the start of combination antiretroviral therapy, an inflammatory reaction to asymptomatic or residual opportunistic infections may arise; autoimmune disorders such as Graves' disease and autoimmune hepatitis have also been reported in the setting of immune reactivation, sometimes many months after initiation
  • Osteonecrosis (§4.8): reported, frequency unknown, 'particularly in patients with generally acknowledged risk factors, advanced HIV disease or long-term combined antiretroviral exposure'
  • Mitochondrial dysfunction after in-utero and/or post-natal exposure to nucleoside analogues (§4.4): mainly haematological (anaemia, neutropenia) and metabolic (hyperlactataemia, hyperlipasaemia) disorders, often transitory; rare late-onset neurological disorders (hypertonia, convulsion, abnormal behaviour)

Monitoring

  • Renal function — dosing is banded by creatinine clearance, and §4.4 states 'In patients with moderate to severe renal impairment, the terminal plasma half-life of lamivudine is increased due to decreased clearance, therefore the dose should be adjusted'
  • Pancreatitis (§4.4): stop Epivir immediately if clinical signs, symptoms or laboratory abnormalities suggestive of pancreatitis occur
  • Blood lipids and glucose (§4.4, verbatim): 'For monitoring of blood lipids and glucose reference is made to established HIV treatment guidelines. Lipid disorders should be managed as clinically appropriate.'
  • Clinical review for opportunistic infections (§4.4, verbatim): patients 'may continue to develop opportunistic infections and other complications of HIV infection, and therefore should remain under close clinical observation by physicians experienced in the treatment of patients with associated HIV diseases'
  • Liver enzymes and haematology, implied by §4.8: transient AST/ALT elevations and hepatitis; neutropenia, anaemia and thrombocytopenia
  • Hepatitis co-infection (§4.6): 'For patients co-infected with hepatitis who are being treated with lamivudine and subsequently become pregnant, consideration should be given to the possibility of a recurrence of hepatitis on discontinuation of lamivudine.'

Clinical monograph

How it works

It is phosphorylated intracellularly to its active triphosphate, which inhibits viral reverse transcriptase and terminates the growing viral DNA chain.

Prescribing in practice

  • In patients co-infected with HIV and hepatitis B, stopping lamivudine can precipitate a severe hepatitis flare, so monitor closely after discontinuation.
  • Doses require adjustment in renal impairment as the drug is renally cleared.
  • Hepatitis B doses differ from HIV doses, and lamivudine must not be used as the only active antiretroviral for HIV to avoid resistance.

Monitoring

Monitor renal function and, in hepatitis B or co-infection, liver function and viral parameters, with vigilance for flares after stopping.

Counselling the patient

  • Take the medicine regularly to keep the virus suppressed and reduce resistance.
  • Do not stop treatment without specialist advice, as your liver infection can flare.
  • Report severe tiredness, muscle pain or breathlessness, which need medical review.

Evidence & guidelines

Lamivudine is an established component of recommended antiretroviral and chronic hepatitis B regimens; refer to BHIVA and NICE guidance.

Reference: BHIVA/EASL guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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