emtricitabine + tenofovir alafenamide fumarate: prescribing and clinical use
Focused clinical detail for use alongside current product information, local policy and patient-specific assessment.
emtricitabine + tenofovir alafenamide fumarate: clinical details
Prescribing considerations
- Before PrEP, confirm HIV-negative status and assess for possible acute infection; this combination alone is inadequate for established HIV.
- For PrEP, explain adherence, continuing HIV testing and broader STI-prevention measures.
- Review hepatitis B status before starting or stopping because withdrawal can precipitate severe hepatitis exacerbation.
- Avoid in treatment-experienced HIV-1 with the K65R mutation; consider resistance history.
- Consider renal function, liver disease, interacting transporter inducers or inhibitors, and limited evidence in some PrEP populations.
Contraindications and cautions
- Hypersensitivity to either active substance or an excipient.
- Use as PrEP when HIV-1 status is unknown.
Monitoring
- HIV testing before and regularly during PrEP, with investigation for suspected acute HIV infection.
- Renal function before or at initiation and during therapy as clinically appropriate.
- Clinical and laboratory follow-up after withdrawal in people with hepatitis B.
- For HIV treatment, virological response and other routine disease-specific parameters.
- Weight, blood glucose and lipid changes as clinically appropriate during antiretroviral therapy.
Clinical pharmacology
Emtricitabine is converted intracellularly to an active triphosphate and tenofovir alafenamide to tenofovir diphosphate. Both inhibit reverse transcriptase through DNA incorporation and chain termination. Tenofovir alafenamide concentrates active tenofovir within HIV target cells while producing lower circulating tenofovir exposure than tenofovir disoproxil.
Formulation and product differences
- The selected product is a film-coated oral tablet that can be taken with or without food and split for immediate administration.
- A formulation containing less tenofovir alafenamide is used with certain pharmacokinetic boosters; the formulations are not automatically interchangeable.
emtricitabine + tenofovir alafenamide fumarate preparations and strengths
Tablet
Route: Oral
Strengths: 200 mg + 10 mg, 200 mg + 25 mg
emtricitabine + tenofovir alafenamide fumarate interactions
Ask the HIV or PrEP team to check all prescribed, non-prescribed and herbal products. Important examples include:
Rifampicin, rifabutin or rifapentine
May lower tenofovir alafenamide exposure, risking reduced effect and resistance; co-administration is not recommended.
Carbamazepine, oxcarbazepine, phenobarbital or phenytoin
May substantially reduce tenofovir alafenamide exposure; co-administration is not recommended.
St John's wort
May reduce tenofovir alafenamide exposure and should not be used with this combination.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.