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.
Rezolsta is a fixed-dose combination tablet containing darunavir 800mg and cobicistat 150mg. It’s used as part of a combination antiretroviral regimen for HIV-1 treatment. Darunavir is a protease inhibitor that blocks HIV replication, while cobicistat is a pharmacokinetic booster that increases darunavir levels in the blood, allowing once-daily dosing.
How Does Rezolsta Work?
Darunavir blocks the HIV protease enzyme, preventing the virus from producing functional proteins needed to create new copies of itself. Cobicistat inhibits the liver enzyme (CYP3A4) that breaks down darunavir, keeping drug levels high enough for once-daily dosing.
Rezolsta must be taken with other antiretroviral drugs (usually two NRTIs like tenofovir/emtricitabine) to form a complete treatment regimen.
Dosage and How to Take It
- One tablet once daily with food
- Food is essential — it increases absorption by approximately 30%
- Take at the same time each day
- Swallow whole with water
Side Effects
- Diarrhoea (most common, usually mild)
- Nausea
- Headache
- Rash (usually mild; stop and seek advice if severe)
- Raised cholesterol and triglycerides
Who Is Rezolsta For?
Rezolsta is used for people with HIV who have no darunavir resistance mutations. It’s suitable for both treatment-naive patients and those switching from another regimen. It’s particularly useful for patients who cannot take integrase inhibitors.
Read more: What is HIV? | One-pill-a-day treatments
Frequently Asked Questions
Is Rezolsta one pill a day?
Rezolsta itself is one tablet, but you also need to take backbone drugs (e.g., tenofovir/emtricitabine as a separate tablet). So the total is usually two tablets daily.
Can I take Rezolsta with food?
You must take it with food. Taking it on an empty stomach significantly reduces absorption and may lead to treatment failure.
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.
