Pharmacology · Nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs)
Emtricitabine !
An NRTI almost twin to lamivudine. Usually combined with tenofovir in one tablet, to treat HIV or prevent it (PrEP).
Updated 2026-11-01
Also called: FTC
The figure shows emtricitabine triphosphate, the active form, in the polymerase site of HIV-1 reverse transcriptase with DNA.
Mechanism of action
A fluorinated cytidine analogue, very similar to lamivudine. It is phosphorylated to emtricitabine triphosphate, which competes with dCTP and ends the viral DNA chain. It selects the same M184V/I resistance mutation.
- It is phosphorylated to emtricitabine triphosphate
- It competes with dCTP at reverse transcriptase
- It is built in and ends the viral DNA chain
Pharmacokinetics
- Elimination
- By the kidney, through filtration and tubular secretion; adjusted in kidney failure
- Half-life
- Plasma half-life about 10 hours
Indications
- HIV-1 infection, combined with other antiretrovirals HIV infection and AIDS →
- Pre-exposure prophylaxis (PrEP), combined with tenofovir HIV infection and AIDS →
Adverse effects
Common
- Headache, diarrhoea, nausea
- Tiredness, dizziness, insomnia
- Rash
- Skin hyperpigmentation (palms and soles), very common in children
Contraindications
- Previous hypersensitivity to emtricitabine
Key interactions
- Lamivudine
- Same mechanism and resistance: not combined
- Drugs cleared by tubular secretion
- They can compete for renal elimination and raise either drug's levels
What is monitored
- Hepatitis B serology before starting
- Kidney function
- Viral load and CD4; in PrEP, regular HIV tests
Administration and safety
- By mouth, as a capsule, solution or within fixed-dose combinations
- Check it is not given together with lamivudine by duplication error
Nursing care
- Check hepatitis B status
- Explain that dark spots on palms and soles are expected and not dangerous
- In PrEP, reinforce adherence and HIV testing
Pregnancy and breastfeeding
Antiretroviral treatment in pregnancy protects the mother and lowers HIV transmission to the baby; the treating team chooses the regimen.
Test yourself
Think of the answer, then tap the question to see it.
Which drug is emtricitabine combined with in oral PrEP?
With tenofovir (disoproxil or alafenamide).
Which skin effect is typical of emtricitabine?
Hyperpigmentation of palms and soles, very common in children.
Which mutation gives resistance to emtricitabine and lamivudine?
M184V (or M184I) in reverse transcriptase.
Related drugs
Related conditions
← Back to the class: Nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs)
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - EMTRICITABINE capsule (DailyMed (U.S. National Library of Medicine), 2026); Emtricitabine: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2025); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026); eEML - Electronic Essential Medicines List (World Health Organization, 2025).
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Representative model, for educational purposes only.