Lamivudine is an antiviral medicine used to treat chronic hepatitis B, in patients with active viral replication and liver inflammation. It reduces virus multiplication and helps control the disease. Because resistance can develop, treatment must be well planned and followed up by a doctor.
Also known as: Epivir, 3TC
Emtricitabine and lamivudine have identical mechanisms of action (cytosine analogues). Coadministration offers no additional benefit and may increase toxicity.
Emtricitabine and lamivudine are both cytosine analogues that act as chain terminators on HIV reverse transcriptase. They have identical mechanisms of action, cross-resistance profiles and elimination pathways (both essentially renally eliminated). Coadministration does not offer clinically significant synergy — it only doubles potential side effects (nausea, headache, elevated transaminases) without additive antiretroviral benefit. In clinical practice, only one of the two is chosen as the NRTI backbone (usually lamivudine as it is better studied and has more available fixed-dose formulations). The FTC/TDF combination (Truvada) is an option, but not with lamivudine.
Emtricitabine + lamivudine: identical mechanism (cytosine analogues). Do not coadminister — no additive benefit.
Both are cytosine analogues that act as chain terminators on reverse transcriptase. There is no clinically significant synergy — only duplication of side effects.
None (should not be used together).
None (unnecessary duplication).
DO NOT coadminister. Choose only one of the two as the NRTI backbone.
DailyMed/FDA (NIH/NLM) — approved Emtricitabine (Emtriva) label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=d6599395-3944-44f9-97f2-e0424c6b6a1f ; approved Lamivudine label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=cb340b00-f2a8-48e7-af4b-07b3d6a1f5c3
Combining Lamivudine with Co-trimoxazole increases Lamivudine concentrations, with a risk of toxicity.
Lamivudine is predominantly eliminated by active renal secretion of organic cations, and trimethoprim (a co-trimoxazole component) inhibits those transporters (OCT), raising lamivudine plasma concentrations; the lamivudine label states this interaction is not considered clinically significant and that no lamivudine dose adjustment is needed. The co-trimoxazole label, however, recommends avoiding co-administration with OCT2 substrates whenever possible. In practice, the combination is common (HIV prophylaxis) and well tolerated; monitor for haematological or hepatic toxicity in susceptible patients.
Co-trimoxazole + lamivudine: trimethoprim inhibits OCT2 and raises lamivudine levels. No dose adjustment, but monitor for toxicity.
Trimethoprim reduces the renal tubular secretion of Lamivudine (via organic cation transport), increasing its exposure by about 40%.
Renal function and signs of Lamivudine toxicity (pancreatitis, anaemia, peripheral neuropathy).
Signs of Lamivudine toxicity (nausea, abdominal pain, anaemia, neuropathy) require reassessment.
Maintain surveillance; adjust the Lamivudine dose in renal impairment and watch for toxicity in prolonged therapy.
DailyMed/FDA (NIH/NLM) — approved Lamivudine label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=6bd6b9da-df69-46db-813e-4e7f3bdecf95 ; approved Co-trimoxazole label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=08500fcb-dbec-4ac2-91c3-189d27907ec0 — with additional reference: Prontuário Terapêutico do INFARMED, INFARMED (11th ed., 2012)
Abacavir and lamivudine are frequently combined in first-line regimens (2 NRTIs). There is no clinically significant adverse interaction.
Abacavir and lamivudine are frequently combined as the NRTI backbone in first-line HIV regimens (e.g. ABC + 3TC + DTG, or ABC + 3TC + EFV). Both act as nucleoside/nucleotide reverse transcriptase analogues, but do not significantly compete for the same metabolic pathways — abacavir is metabolised by alcohol dehydrogenase and UGT1A1, while lamivudine is excreted essentially unchanged renally. The combination is synergistic and well tolerated, with a complementary side effect profile. The standard dose is abacavir 600 mg + lamivudine 300 mg, once daily (fixed-dose combination available). The only prerequisite is HLA-B*571 testing before starting abacavir.
Abacavir + lamivudine: intentional first-line combination (2 NRTIs). No adverse interaction — therapeutic synergy.
Both act as nucleoside/nucleotide reverse transcriptase analogues, but do not significantly compete for the same metabolic pathways. The combination is synergistic and well tolerated.
Assess HLA-B*5701 before starting abacavir. Monitor renal function.
None.
No restrictions. Standard dose: abacavir 600 mg + lamivudine 300 mg, once daily.
DailyMed/FDA (NIH/NLM) — approved Abacavir (Ziagen) label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=ca73b519-015a-436d-aa3c-af53492825a1 ; approved Lamivudine label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=cb340b00-f2a8-48e7-af4b-07b3d6a1f5c3
Alcohol may worsen the underlying liver disease (especially in hepatitis B coinfection) during lamivudine treatment.
Limit or avoid alcohol intake during treatment.
DailyMed/FDA (NIH/NLM) — approved Lamivudine label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=6bd6b9da-df69-46db-813e-4e7f3bdecf95
Lamivudine can be taken with or without food, with no relevant change in absorption.
May be taken with or without food, consistently.
DailyMed/FDA (NIH/NLM) — approved Lamivudine label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=6bd6b9da-df69-46db-813e-4e7f3bdecf95
Nucleoside analogues, including lamivudine, can cause lactic acidosis and severe hepatic steatosis, sometimes fatal.
Stop with symptoms (nausea, abdominal pain, dyspnoea) or confirmed lactic acidosis.
DailyMed/FDA (NIH/NLM) — approved Lamivudine label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=6bd6b9da-df69-46db-813e-4e7f3bdecf95
Lamivudine is predominantly renally excreted; in renal impairment the dose must be adjusted to avoid toxicity.
Adjust the dose to creatinine clearance.
DailyMed/FDA (NIH/NLM) — approved Lamivudine label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=6bd6b9da-df69-46db-813e-4e7f3bdecf95
Lamivudine is used in pregnancy to prevent vertical transmission of HIV; it is not a known teratogen at therapeutic doses.
Use in pregnancy as part of the HIV antiretroviral regimen.
Excreted into breast milk; in HIV infection breastfeeding is not recommended regardless of treatment.
No specific additional contraception.
DailyMed/FDA (NIH/NLM) — approved Lamivudine label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=6bd6b9da-df69-46db-813e-4e7f3bdecf95 ; Prontuário Terapêutico do INFARMED (11th ed., 2012) — Annex 2, Drugs and Breastfeeding: Theoretical risk of seizures and neuropathy; give prophylactic pyridoxine to the mother and child.
Clinical and educational support tool. The information does not replace a medical prescription or the opinion of a qualified healthcare professional.
Nucleoside analogue reverse transcriptase inhibitor (NRTI) active against HBV (and HIV); oral bioavailability ~86-87%; renal excretion — adjust in renal impairment. Limitation: resistance (YMDD mutation) with prolonged use.
Intracellularly phosphorylated to lamivudine-triphosphate, which inhibits viral reverse transcriptase by competing with deoxycytidine-triphosphate and chain termination of DNA — blocks HBV and HIV replication.
Well absorbed orally: absolute bioavailability 86±16% (150 mg tablet) and 87±13% (solution); serum peak 1.28±0.56 mcg/mL (HBV) 0.5-2 h after 100 mg; food does not alter absorption; volume of distribution 1.3±0.4 L/kg (extravascular distribution).
Intracellular metabolism (phosphorylation); predominantly renal excretion unchanged (glomerular filtration and active tubular secretion) — extend the dosing interval in renal impairment; minor hepatic oxidative metabolism.
Plasma half-life ~5-7 h; the intracellular half-life of lamivudine-triphosphate is 13-19 h (supports once-daily dosing in hepatitis B); no relevant accumulation with repeated dosing.
Medicines from the same therapeutic group (ATC classification) or the same pharmacological class.
