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.
Zidovudine (also called AZT, ZDV, or brand name Retrovir) was the first drug approved to treat HIV, licensed in 1987. It’s a nucleoside reverse transcriptase inhibitor (NRTI) that remains part of some combination regimens today, though newer drugs have largely replaced it as first-line therapy.
Zidovudine holds historical significance as the drug that transformed HIV from a rapidly fatal diagnosis into a manageable condition, though modern treatments are now far more effective and better tolerated.
How Does Zidovudine Work?
Zidovudine blocks HIV’s reverse transcriptase enzyme, which the virus needs to convert its RNA into DNA. Without working reverse transcriptase, HIV cannot copy its genetic material into host cells and cannot replicate.
When Is Zidovudine Still Used?
- As part of combination therapy in resource-limited settings where newer drugs aren’t available
- In pregnancy, historically used to prevent mother-to-child transmission (though now replaced by more effective options in most settings)
- In newborns as post-exposure prophylaxis to prevent HIV transmission from an HIV-positive mother
- Occasionally in salvage regimens when other drugs have failed
Side Effects
- Anaemia and neutropenia (low blood counts)
- Fatigue
- Nausea, headache
- Muscle pain (myopathy) with long-term use
- Lipodystrophy with prolonged use
- Lactic acidosis (rare but serious)
These side effects, particularly anaemia and lipodystrophy, are why zidovudine is rarely used in first-line treatment today.
Read more: What is HIV? | Starting HIV treatment | Lipodystrophy
Frequently Asked Questions
Is AZT still used in 2026?
Rarely in high-income settings. Modern integrase inhibitor-based regimens are preferred due to better efficacy, tolerability, and fewer long-term side effects. Zidovudine is still used in specific situations, particularly for newborn post-exposure prophylaxis.
Why was AZT so important historically?
Before AZT, HIV was almost always fatal. AZT was the first drug shown to slow disease progression and extend life. It paved the way for the combination antiretroviral therapy (cART) revolution of the mid-1990s.
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.
