Recommended Use and Dosage of Emtricitabine for HIV-1 Infection Treatment
Emtricitabine is indicated in combination with other antiretroviral agents for the treatment of HIV-1 infection, with the standard adult dosage being one 200 mg capsule taken once daily orally, with or without food. 1
Dosage Recommendations
Adult Patients (18 years and older)
- One 200 mg capsule administered once daily orally
- May be taken without regard to food 1
Pediatric Patients
- For children weighing more than 33 kg who can swallow an intact capsule: one 200 mg capsule administered once daily orally 1
Dosage Adjustment for Renal Impairment
Dose interval adjustments are required based on creatinine clearance:
| Creatinine Clearance (mL/min) | Dosing Recommendation |
|---|---|
| ≥50 mL/min | 200 mg every 24 hours |
| 30-49 mL/min | 200 mg every 48 hours |
| 15-29 mL/min | 200 mg every 72 hours |
| <15 mL/min or on hemodialysis | 200 mg every 96 hours |
For hemodialysis patients: If dosing on day of dialysis, give dose after dialysis 1
Clinical Use in HIV Treatment Regimens
Emtricitabine is typically used as part of a combination antiretroviral therapy (ART) regimen. It is commonly paired with:
Tenofovir disoproxil fumarate (TDF) or tenofovir alafenamide (TAF) as part of the nucleoside/nucleotide reverse transcriptase inhibitor (NRTI) backbone in:
- Integrase strand transfer inhibitor (InSTI)-based regimens
- Non-nucleoside reverse transcriptase inhibitor (NNRTI)-based regimens
- Protease inhibitor (PI)-based regimens 2
Common combination regimens include:
- Emtricitabine/TDF with efavirenz
- Emtricitabine/TDF with rilpivirine
- Emtricitabine/TDF or emtricitabine/TAF with boosted darunavir 2
Required Testing Before Initiation
Before starting emtricitabine:
- HIV testing to confirm infection
- Hepatitis B virus (HBV) testing (mandatory due to risk of severe acute exacerbation of hepatitis B upon discontinuation) 1
- Serum creatinine with estimated glomerular filtration rate
- Comprehensive STI screening 3
Monitoring During Treatment
- HIV RNA level: Within first 6 weeks of starting therapy, then every 3 months until <50 copies/mL for 1 year, then every 6 months
- CD4 cell count: Every 6 months until >250/μL for 1 year, then can stop as long as virus is suppressed
- Renal function: At least every 6 months 2, 1
Important Warnings and Precautions
Severe Acute Exacerbation of Hepatitis B:
- All patients should be tested for HBV before starting emtricitabine
- Severe acute exacerbations of hepatitis B have been reported in patients coinfected with HIV-1 and HBV who discontinue emtricitabine
- Hepatic function should be closely monitored with both clinical and laboratory follow-up for at least several months after discontinuation 1
Immune Reconstitution Syndrome:
- May occur after initiating combination antiretroviral therapy
- Requires clinical evaluation and may necessitate additional treatment 1
Lactic Acidosis/Severe Hepatomegaly with Steatosis:
- Discontinue treatment in patients who develop symptoms or laboratory findings suggestive of lactic acidosis or pronounced hepatotoxicity 1
Use in HIV Prevention (PrEP)
Emtricitabine is also used in combination with tenofovir disoproxil fumarate for HIV pre-exposure prophylaxis (PrEP):
- Daily TDF/emtricitabine is the recommended regimen for men and women at risk of sexual exposure and people who inject drugs 2, 3
- Pericoital TDF/emtricitabine (2-1-1 dosing) may be considered as an alternative to daily PrEP for MSM with infrequent sexual exposures 3
Common Adverse Effects
Most common adverse reactions (incidence ≥10%) include:
- Headache, diarrhea, nausea, fatigue, dizziness
- Depression, insomnia, abnormal dreams
- Rash, abdominal pain, asthenia
- Increased cough and rhinitis
- Skin hyperpigmentation (very common in pediatric patients) 1
Contraindications
Emtricitabine is contraindicated in patients with previously demonstrated hypersensitivity to any of the components of the product 1.