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.
Azithromycin is a macrolide antibiotic used in sexual health for treating certain STIs. It was previously the standard single-dose treatment for chlamydia, but UK guidelines now prefer doxycycline as first-line. Azithromycin still has important roles in treating mycoplasma genitalium (when no resistance is present) and as part of combination regimens.
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Current Uses
| Condition | How Azithromycin Is Used |
|---|---|
| Chlamydia | Alternative when doxycycline isn’t suitable |
| Mycoplasma genitalium | Part of sequential treatment (after doxycycline) |
| Pregnancy STIs | Alternative to doxycycline (which is avoided) |
| LGV | Not first-line (doxycycline preferred) |
Why Doxycycline Replaced It for Chlamydia
- Doxycycline has higher cure rates
- Single-dose azithromycin promoted Mgen resistance
- 7-day doxycycline is more reliable
Side Effects
- Nausea
- Diarrhoea
- Abdominal pain
- Generally well tolerated
Dosing
- Chlamydia: 1g stat then 500mg daily for 2 days (when used)
- Varies by condition — follow your prescription
Read more: Doxycycline | Best antibiotics for STIs | Mgen
Frequently Asked Questions
Is azithromycin still used for chlamydia?
As an alternative — doxycycline is now preferred.
Can I take it during pregnancy?
Yes — it’s the preferred chlamydia treatment in pregnancy.
Does it interact with HIV medication?
Generally safe — check with your pharmacist.
Related reading
- Using Antibiotics to Prevent STIs: DoxyPEP Explained
- Best Antibiotics for STIs: A Practical Guide
- Ciprofloxacin for STIs: Uses, Dosage, and Side Effects
- Clindamycin: Uses in Sexual Health
- Diflucan (Fluconazole): What It Does
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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