Pharmacology · Nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs)
Tenofovir alafenamide !
A newer tenofovir prodrug: it enters cells before activation, leaves little tenofovir in blood, and so harms kidney and bone less.
Updated 2026-11-01
Also called: TAF
The figure shows tenofovir diphosphate, the active form that tenofovir alafenamide also produces, as the incoming nucleotide in HIV-1 reverse transcriptase.
Mechanism of action
It circulates mostly as intact prodrug; once inside lymphocytes and liver cells it becomes tenofovir and then tenofovir diphosphate, which ends the DNA chain of HIV and hepatitis B virus. Because free plasma tenofovir is much lower than with disoproxil, less reaches the kidney tubule and bone.
- It circulates as intact prodrug
- Inside the cell it becomes tenofovir diphosphate
- It ends the viral DNA chain
- Little free tenofovir reaches kidney and bone
Pharmacokinetics
- Absorption
- Oral; the hepatitis B product is taken with food
- Distribution
- Concentrates inside cells; little free tenofovir in plasma
Indications
- HIV-1 infection, within combinations with other antiretrovirals HIV infection and AIDS →
- Chronic hepatitis B Viral hepatitis →
Adverse effects
Common
- Headache
- Nausea
- Tiredness
Contraindications
- Hypersensitivity to tenofovir alafenamide
Key interactions
- St John's wort
- Lowers levels and can cause treatment failure
- NSAIDs
- Higher kidney risk; avoided or monitored
What is monitored
- HIV and hepatitis B tests before starting
- Kidney function
- Liver tests for months if stopped in hepatitis B
Administration and safety
- By mouth
- Do not swap with tenofovir disoproxil without an explicit order: the names look alike but the products are not equivalent
- If the person has untreated HIV, the hepatitis-B-only product can induce HIV resistance
Nursing care
- Confirm HIV and hepatitis B tests
- Teach not to run out of medicine (hepatitis B flare risk)
- Ask about anti-inflammatories and herbal products
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.
Why is tenofovir alafenamide less nephrotoxic than disoproxil?
It is activated mainly inside cells and leaves much less free plasma tenofovir, which is what harms the kidney tubule.
Which two infections does tenofovir alafenamide treat?
HIV-1 infection (in combinations) and chronic hepatitis B.
What is the risk of using the hepatitis B product in someone with untreated HIV?
That HIV is exposed to a single drug and develops resistance.
Related drugs
Related conditions
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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Tenofovir alafenamide: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2025); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 64 (McGraw Hill, 2023).
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Representative model, for educational purposes only.