Emtricitabine

Pronunciation: em-tri-SITE-a-been.

Generic name
emtricitabine
Brand names
Emtriva (standalone, all 6 markets reviewed), Truvada and generic emtricitabine/tenofovir disoproxil fumarate (with tenofovir DF), Descovy (with tenofovir alafenamide), Atripla (with efavirenz/tenofovir DF), Complera/Eviplera (with rilpivirine/tenofovir DF), Genvoya and Stribild (with elvitegravir/cobicistat/tenofovir)
Drug class
Nucleoside reverse transcriptase inhibitor (NRTI), antiretroviral
Form
Capsule (200 mg) or oral solution (10 mg/mL) as standalone Emtriva; tablet as part of a fixed-dose combination product
Route
Oral
Legal status
Prescription-only in all markets reviewed.

Availability and supply rules vary by country

Trade names by country: United States · United Kingdom · Canada · Australia · New Zealand

Australia: Emtriva (7), Eviplera, Atripla, Truvada, Stribild, Genvoya, Descovy, Biktarvy (fixed-dose combinations) (7) · Full directory

What emtricitabine is and how it works

Emtricitabine is a prescription antiviral medicine (a nucleoside reverse transcriptase inhibitor) used together with other antiretroviral medicines to treat HIV-1 infection. It is sold on its own as Emtriva, and -- far more commonly -- as part of combination tablets such as Truvada, Descovy, Atripla, Complera, Genvoya, Stribild, Odefsey, and Biktarvy, which combine it with one or more other HIV medicines in a single pill. (1) (3)

Emtricitabine carries a genuine boxed warning covering two real risks: lactic acidosis and severe liver problems (rare but sometimes fatal), and severe worsening of hepatitis B in people who have both HIV and hepatitis B and then stop taking emtricitabine. Emtricitabine is never used alone for HIV-1 -- it is always part of a combination regimen. Always take it exactly as prescribed, get tested for hepatitis B before starting, and never stop it without talking to your prescriber first, since stopping can trigger a dangerous flare of hepatitis B in coinfected patients.

Mechanism of action: how emtricitabine works

Emtricitabine 5'-triphosphate inhibits HIV-1 reverse transcriptase by competing with the natural substrate deoxycytidine 5'-triphosphate and by being incorporated into nascent viral DNA, causing chain termination. Absolute bioavailability is approximately 93% (capsules) or 75% (oral solution); plasma half-life is approximately 10 hours; elimination is primarily renal. (1) (8)

What emtricitabine is used for

HIV-1 infection (in combination therapy)

Used together with other antiretroviral medicines -- either as separate tablets or within a combination pill (Truvada, Descovy, Atripla, Complera, Genvoya, Stribild, Odefsey, or Biktarvy) -- to treat HIV-1 infection in adults and children. Never used alone. (1) (3)

Before taking emtricitabine

Do not take / not appropriate for

  • Do not take emtricitabine if you have had a hypersensitivity (allergic) reaction to emtricitabine or any ingredient in the product. (all countries) (1) (3)
  • Do not take emtricitabine together with Atripla, Complera/Eviplera, Truvada, or any other product that already contains emtricitabine or lamivudine, since these combinations would duplicate the same or a very similar medicine. (all countries) (1)

Tell your clinician about

  • Whether you have, or have ever had, hepatitis B infection -- you should be tested for hepatitis B before starting emtricitabine.
  • Any history of liver disease or kidney disease.
  • Whether you are pregnant, planning to become pregnant, or breastfeeding.
  • All other medicines you take, especially any other HIV medicines, to avoid duplicating emtricitabine or a similar ingredient.
  • Whether you have ever had a build-up of lactic acid or severe liver problems on any nucleoside-analogue medicine.
(1) (3)

How to take emtricitabine

  • Take emtricitabine exactly as your prescriber directs, at around the same time each day, together with your other prescribed antiretroviral medicines.
  • Emtriva capsules can be taken with or without food.
  • Do not stop taking emtricitabine without talking to your prescriber first, even if you feel well -- stopping abruptly, especially if you also have hepatitis B, can lead to a serious, sudden worsening of hepatitis B that needs prompt medical monitoring.
  • If you are taking a combination tablet (such as Truvada, Descovy, Atripla, Complera, Genvoya, Stribild, Odefsey, or Biktarvy), follow the specific instructions for that product rather than the standalone Emtriva instructions.
(1) (3)

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2) (3) (4) (5) (6) (7) (8)

Missed dose

If you miss a dose, take it as soon as you remember, then take your next dose at its regular scheduled time -- do not take a double dose. If you are unsure, ask your pharmacist or prescriber, since keeping antiretroviral dosing consistent is important.

Overdose

Seek urgent medical advice if too much emtricitabine has been taken. There is no known specific antidote; single doses up to 1200 mg have not caused severe reactions, and haemodialysis removes only about 30% of a dose over a 3-hour session, so overdose management is supportive and should be directed by a clinician or emergency service. (1)

Side effects

Side effects and their urgency vary; report severe, persistent, or concerning symptoms.

Headache.

What to notice: Headache.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1) (3)

Diarrhoea and nausea.

What to notice: Diarrhoea and nausea.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1) (3)

Fatigue, dizziness, and insomnia or abnormal dreams.

What to notice: Fatigue, dizziness, and insomnia or abnormal dreams.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)

Skin rash, or in some patients, patchy skin darkening (hyperpigmentation), which is more common in children.

What to notice: Skin rash, or in some patients, patchy skin darkening (hyperpigmentation), which is more common in children.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1) (3)

Elevated creatine kinase on blood tests.

What to notice: Elevated creatine kinase on blood tests.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (3)

Serious warnings

Lactic acidosis and severe liver problems — boxed_warning

Symptoms: Unusual tiredness or weakness, unexpected muscle pain, trouble breathing, stomach pain with nausea or vomiting, feeling cold (especially in the arms and legs), dizziness, or a fast or irregular heartbeat.

Action: Seek emergency medical help immediately -- this is a rare but genuinely serious, sometimes fatal reaction that your care team needs to assess and manage right away. (1)

Worsening of hepatitis B after stopping emtricitabine (in people with HIV and HBV together) — boxed_warning

Symptoms: Not applicable in advance -- this is a proactive warning about what can happen after stopping the medicine, monitored through liver blood tests rather than waiting for symptoms.

Action: Never stop emtricitabine on your own. If you have both HIV and hepatitis B, your prescriber will monitor your liver function closely, both clinically and with blood tests, for at least several months after emtricitabine is stopped, because a sudden, severe flare of hepatitis B can occur and may need treatment. (1)

Kidney problems — high caution

Symptoms: Reduced urination, swelling in the legs or ankles, or unusual tiredness.

Action: Contact your prescriber promptly for kidney-function tests -- your dose or dosing interval may need adjusting, especially if you have existing kidney impairment. (1) (3)

Immune reconstitution syndrome — high caution

Symptoms: New or worsening symptoms of an infection shortly after starting treatment, as your immune system recovers.

Action: Contact your prescriber if you notice new symptoms of infection or inflammation soon after starting emtricitabine-based treatment -- this can be a sign that your immune system is responding to a previously hidden infection and needs assessment. (1) (3)

Interactions

  • Do not combine emtricitabine with other medicines that also contain emtricitabine or lamivudine (such as Atripla, Complera/Eviplera, or Truvada if you are also taking standalone Emtriva) -- this would duplicate the same or a very similar active ingredient. (1)
  • No clinically significant interactions were found in studies with zidovudine, indinavir, stavudine, famciclovir, or tenofovir disoproxil fumarate; emtricitabine does not inhibit human CYP450 liver enzymes. (1)
  • Always tell your prescriber about every other medicine you take, since emtricitabine is generally combined with other antiretrovirals that carry their own separate interactions. (3)

Pregnancy, breastfeeding, kidney/liver function, age

Pregnancy

Emtricitabine may be considered for use during pregnancy if needed, based on the current evidence reviewed; animal studies did not show increased fetal harm at doses far higher than the human dose. Pregnancy decisions should always be made together with your prescriber, weighing the benefits of HIV treatment against any risks. (1) (2) (3) (4) (5) (6) (7) (8)

Breastfeeding

Breastfeeding is not recommended while taking emtricitabine, primarily because of the risk of passing HIV to the infant through breast milk, not because of the medicine's safety alone. (1) (2) (3) (4) (5) (6) (7) (8)

Children

Emtriva is authorised for children from 4 months of age (UK/EU) or with pediatric dosing from birth in some markets (US), with dosing based on body weight for the oral solution. (1) (2) (3) (4) (5) (6) (7) (8)

Elderly

Clinical trials did not include enough patients aged 65 and over to determine whether they respond differently; dose selection should be cautious, generally starting at the lower end of the dosing range and considering kidney function. (1) (2) (3) (4) (5) (6) (7) (8)

Hepatic_impairment

Specific dosing guidance for liver impairment was not detailed in the sources reviewed for this dossier; discuss with your prescriber if you have liver disease. (1) (2) (3) (4) (5) (6) (7) (8)

Renal_impairment

Requires a longer dosing interval, adjusted according to creatinine clearance -- every 24 hours if creatinine clearance is 30 mL/min or higher, every 72 hours for 15-29 mL/min, and every 96 hours for less than 15 mL/min, per the reviewed UK labelling. (1) (2) (3) (4) (5) (6) (7) (8)

Monitoring

Before starting

  • Testing for hepatitis B virus infection
  • Baseline kidney function
  • Review of all other medicines, to avoid duplicating emtricitabine or lamivudine

During treatment

  • Kidney function monitored periodically, especially in those with existing kidney impairment.
  • Liver function monitored closely, both clinically and with blood tests, for at least several months if emtricitabine is stopped in someone coinfected with hepatitis B.
  • Watching for signs of lactic acidosis or severe liver problems, and for new or worsening infection symptoms shortly after starting treatment (immune reconstitution).
(1) (3)

Storage

Store capsules at controlled room temperature, 25degC (77degF), with excursions permitted between 15-30degC (59-86degF). Store the oral solution refrigerated at 2-8degC (36-46degF); it may be kept at room temperature for up to 3 months. Keep out of reach of children.

Professional information

Clinician-facing context only, sourced from the current US FDA Emtriva prescribing information and current UK emc Emtriva SmPC; verify against the current full local label before prescribing.

United States

Indication: HIV-1 infection, in combination with other antiretrovirals

Dose summary: Capsule: 200 mg once daily. Oral solution: 240 mg (24 mL) once daily (adults); pediatric oral solution 3 mg/kg once daily (0-3 months) or 6 mg/kg once daily up to 240 mg max (3 months-17 years); 200 mg capsule once daily for children >33 kg able to swallow capsules.

Renal context: Dose/dosing-interval adjustment required for creatinine clearance <50 mL/min, per a dedicated dosing table in the full label. (1)

United Kingdom / European Union

Indication: HIV-1 infection in adults and children aged 4 months and over, in combination with other antiretrovirals

Dose summary: 200 mg capsule once daily, with or without food. Children >=33 kg able to swallow capsules: one 200 mg capsule daily.

Renal context: CrCl >=30 mL/min: every 24 hours. 15-29 mL/min: every 72 hours. <15 mL/min: every 96 hours. (3)

Mechanism of action

Hepatic guidance

Specific hepatic-impairment dosing guidance was not detailed in the sources reviewed for this dossier.

Overdose note

No known antidote. Single doses up to 1200 mg have not produced severe adverse reactions. Haemodialysis removes approximately 30% of an emtricitabine dose over a 3-hour session. (1) (8)

Frequently asked questions

Does emtricitabine have a boxed warning?

Yes. Emtricitabine's current US FDA label carries a two-part boxed warning: lactic acidosis and severe liver problems (rarely fatal) reported with nucleoside-analogue medicines, and severe worsening of hepatitis B reported after stopping emtricitabine in people who have both HIV-1 and hepatitis B. Never stop taking it without talking to your prescriber first. (1)

Is emtricitabine used on its own?

No. Emtricitabine is always used together with other antiretroviral medicines for HIV-1 treatment -- either as separate tablets alongside standalone Emtriva, or, far more commonly, as part of a combination tablet such as Truvada, Descovy, Atripla, Complera, Genvoya, Stribild, Odefsey, or Biktarvy. (1) (2)

Why do I need a hepatitis B test before starting emtricitabine?

Because emtricitabine is active against hepatitis B virus even though it is not approved to treat chronic hepatitis B on its own, stopping it in someone who has both HIV and hepatitis B can trigger a severe, sudden worsening of the hepatitis B. Testing beforehand lets your prescriber plan safe monitoring, especially around any future treatment change. (1)

What is the mechanism of action of emtricitabine?

Emtricitabine 5'-triphosphate inhibits HIV-1 reverse transcriptase by competing with the natural substrate deoxycytidine 5'-triphosphate and by being incorporated into nascent viral DNA, causing chain termination. Absolute bioavailability is approximately 93% (capsules) or 75% (oral solution); plasma half-life is approximately 10 hours; elimination is primarily renal. (1) (8)

What is the generic name of Emtricitabine?

The generic name is emtricitabine. It is sold under brand names including Emtriva (standalone, all 6 markets reviewed), Truvada and generic emtricitabine/tenofovir disoproxil fumarate (with tenofovir DF), Descovy (with tenofovir alafenamide), Atripla (with efavirenz/tenofovir DF), Complera/Eviplera (with rilpivirine/tenofovir DF), Genvoya and Stribild (with elvitegravir/cobicistat/tenofovir). (1) (3) (2)

What class of drug is emtricitabine?

Emtricitabine is classed as: Nucleoside reverse transcriptase inhibitor (NRTI), antiretroviral. (1) (3) (2)

References

  1. EMTRIVA (emtricitabine) capsule / oral solution -- full prescribing informationU.S. Food and Drug Administration / DailyMed (NIH), full prescribing information · United States · accessed 2026-07-30 · source 1
  2. TRUVADA / DESCOVY / BIKTARVY -- boxed-warning and market-presence context for emtricitabine-containing fixed-dose combinationsWeb-search summary of U.S. FDA/DailyMed prescribing information for emtricitabine-containing combination products (Truvada, Descovy, Biktarvy) · United States · accessed 2026-07-30 · source 2
  3. Emtriva 200 mg Hard Capsules (emtricitabine) -- Summary of Product Characteristicselectronic medicines compendium (emc), United Kingdom -- Gilead Sciences Ltd · United Kingdom · accessed 2026-07-30 · source 3
  4. Emtriva (emtricitabine) -- European Public Assessment Report (EPAR)European Medicines Agency (EMA) -- centralised procedure EPAR · European Union · accessed 2026-07-30 · source 4
  5. Truvada (emtricitabine/tenofovir disoproxil) -- European Public Assessment Report (EPAR), plus multiple EMA-authorised generic emtricitabine/tenofovir disoproxil products (Krka, Zentiva, Mylan/Viatris)European Medicines Agency (EMA) -- centralised procedure EPAR · European Union · accessed 2026-07-30 · source 5
  6. EMTRIVA (emtricitabine) and TRUVADA (emtricitabine/tenofovir disoproxil fumarate) -- Product MonographsHealth Canada product monograph / Notice of Compliance and Drug Product Database · Canada · accessed 2026-07-30 · source 6
  7. EMTRIVA (emtricitabine) ARTG registration, plus AusPARs for emtricitabine-containing combination products (Truvada, Eviplera, Atripla, Stribild, Genvoya, Descovy, Biktarvy)Therapeutic Goods Administration (TGA), Australia -- Australian Register of Therapeutic Goods (ARTG) and AusPARs · Australia · accessed 2026-07-30 · source 7
  8. EMTRIVA (emtricitabine) -- New Zealand Data Sheet, plus data sheets for Descovy, Genvoya, Odefsey, Biktarvy, and generic tenofovir disoproxil/emtricitabine combinationsMedsafe, New Zealand -- New Zealand Data Sheet · New Zealand · accessed 2026-07-30 · source 8

Brand names by country

Single-ingredient emtricitabine names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries

United States

  • Emtriva10 mg/mL, 200 mg · gilead sciences, inc.

United Kingdom

  • Emtriva (3)MHRA licensed emc smpc confirmed · 200 mg capsule · Gilead Sciences Ltd

Canada

  • Emtriva (6)Health Canada notice of compliance 2005 · 200 mg capsule · Gilead Sciences Inc.
  • Truvada, Descovy (fixed-dose combinations) (6)Health Canada product monograph listed · 200 mg emtricitabine component · Gilead Sciences Inc.

Australia

  • Emtriva (7)TGA ARTG registered 96426 · 200 mg capsule · Gilead Sciences Pty Ltd
  • Eviplera, Atripla, Truvada, Stribild, Genvoya, Descovy, Biktarvy (fixed-dose combinations) (7)TGA ARTG registered · 200 mg emtricitabine component · Gilead Sciences Pty Ltd

New Zealand

  • Emtriva (8)Medsafe data sheet confirmed · 200 mg capsule · not independently confirmed beyond data-sheet/CMI existence in this pass
  • Descovy, Genvoya, Odefsey, Biktarvy, generic tenofovir disoproxil/emtricitabine combinations (8)Medsafe data sheet confirmed · 200 mg emtricitabine component · not independently confirmed beyond data-sheet existence in this pass
View brands in additional countries.

European Union

Emtriva (standalone, EMA centralised authorisation since 2003) (4), Truvada and multiple generic emtricitabine/tenofovir disoproxil combinations (Krka, Zentiva, Mylan/Viatris) (5)

This page provides general reference information about emtricitabine and is not a substitute for advice from the prescriber managing your treatment. All dosing and treatment decisions, including starting, changing, or stopping this medicine, should be made with your prescriber.

Related medicines

Related conditions