References UK clinical guidance from the NHS, the British HIV Association (BHIVA), and the British Association for Sexual Health and HIV (BASHH). Last updated: April 2026.
Emtricitabine/tenofovir disoproxil (brand name Truvada) is a combination antiretroviral tablet used for two purposes: treating HIV infection (as part of a multi-drug regimen) and preventing HIV infection in high-risk individuals (PrEP, pre-exposure prophylaxis). It’s one of the most widely prescribed HIV medications globally.
Need an HIV test before starting PrEP? Order a home test
What Is Emtricitabine/Tenofovir?
Each tablet contains two nucleoside reverse transcriptase inhibitors (NRTIs):
- Emtricitabine 200mg — blocks HIV from copying its genetic material
- Tenofovir disoproxil 245mg — blocks the same step via a different mechanism
Together, they form the “backbone” of most HIV treatment regimens and the standard drug combination for PrEP.
Uses
For HIV treatment
Emtricitabine/tenofovir is taken alongside a third drug (usually an integrase inhibitor like dolutegravir) to form a complete HIV treatment regimen. It is NOT sufficient as HIV treatment on its own. Dose: one tablet once daily.
For PrEP
Taken daily by HIV-negative people at higher risk of exposure. When taken consistently, PrEP reduces the risk of getting HIV from sex by approximately 99%. Available free on the NHS from sexual health clinics.
Read more: What is PrEP? | Truvada
Side Effects
- Nausea, diarrhoea (common in first 1-2 weeks, usually resolves)
- Headache
- Fatigue
- Kidney function changes (requires monitoring with regular blood tests)
- Bone density reduction (small, usually not clinically significant)
Regular monitoring (kidney function and HIV testing for PrEP users) is required. Your clinic will arrange this every 3 months.
Where to Get Emtricitabine/Tenofovir in the UK
- For HIV treatment: Free on NHS prescription from your HIV clinic
- For PrEP: Free from NHS sexual health clinics. You’ll need a negative HIV test and kidney function check before starting
- Generic versions: Available and significantly cheaper than branded Truvada
Frequently Asked Questions
Can I take PrEP only when I need it?
“Event-based” or “on-demand” PrEP dosing is an option for men who have sex with men (not recommended for vaginal sex). The regimen is 2 tablets 2-24 hours before sex, then 1 tablet 24 hours after, then 1 tablet 48 hours after. Discuss with your clinic whether this suits your situation.
Does PrEP protect against other STIs?
No. PrEP only protects against HIV. You can still get chlamydia, gonorrhoea, syphilis, herpes, and other STIs. Regular STI screening is recommended alongside PrEP use.
Related reading
- Choosing the Right PrEP Drug: Truvada vs Descovy
- Dovato for HIV: A Two-Drug Regimen
- Triumeq for HIV: A Straightforward Guide
- Efavirenz for HIV: An Older NNRTI Still in Use
- Eviplera: How This Anti-HIV Drug Works
Sources
- NHS — Sexual health conditions
- BASHH — UK clinical guidelines for STI management
- British HIV Association (BHIVA) — HIV treatment guidelines
- Terrence Higgins Trust — sexual health information
- UK Health Security Agency — STI surveillance data
Steve Page is a recognised expert on Sexually Transmitted Diseases (STDs) and STD treatments, having published numerous articles in peer-reviewed journals and presented his research at conferences around the world. He has an in-depth understanding of the latest medical research on STDs, and is an advocate for the development of new treatments and protocols to improve the health of those affected. In addition to his research, he has dedicated his career to understanding the causes and symptoms of STDs, as well as how to best treat those impacted.
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