Emtricitabine is an antiretroviral of the nucleoside analogue reverse transcriptase inhibitor (NRTI) class. It is used in combination with other antiretrovirals for the treatment of HIV and chronic hepatitis B.
Also known as: Emtriva, FTC
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
Food does not significantly affect emtricitabine absorption.
Can be taken with or without food.
DailyMed/FDA (NIH/NLM) — approved Emtricitabine (Emtriva) label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=d6599395-3944-44f9-97f2-e0424c6b6a1f
Abrupt discontinuation may cause severe hepatitis B exacerbation. Monitor HBV viral load.
DO NOT abruptly discontinue in patients co-infected with hepatitis B.
DailyMed/FDA (NIH/NLM) — approved Emtricitabine (Emtriva) label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=d6599395-3944-44f9-97f2-e0424c6b6a1f
Limited human data. Animal studies did not demonstrate teratogenicity. WHO recommends use during pregnancy.
Can be used in all trimesters when indicated.
Excreted in breast milk. Artificial feeding is recommended for HIV-positive mothers.
Reliable contraceptive methods are recommended.
DailyMed/FDA (NIH/NLM) — approved Emtricitabine (Emtriva) label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=d6599395-3944-44f9-97f2-e0424c6b6a1f
Clinical and educational support tool. The information does not replace a medical prescription or the opinion of a qualified healthcare professional.
Emtricitabine is a cytosine nucleoside analogue that inhibits HIV-1 and HBV reverse transcriptase, acting as both a substrate and inhibitor of the enzyme.
Intracellularly phosphorylated to the active triphosphate (emtricitabine triphosphate), which incorporates into viral DNA and causes chain termination by absence of the 3-OH group. Has a long intracellular half-life, allowing once-daily dosing.
Oral bioavailability: 93% (capsules) and 75% (oral solution). Food does not significantly affect absorption. Tmax: 1-2 hours.
Minimally metabolised — approximately 86% excreted unchanged in urine and 14% in faeces. Does not undergo significant hepatic metabolism. Low interaction potential (does not inhibit CYP).
9-14 hours. Renal elimination: 86% unchanged in urine (renal clearance > glomerular clearance — tubular secretion).
Medicines from the same therapeutic group (ATC classification) or the same pharmacological class.
