Azithromycin
Tablet or syrup
Quick Summary
Azithromycin stops bacteria making proteins. It stays in the body a long time, so courses are short.
Medical Uses
How it's taken
Take it once a day as prescribed.
Take it for the full course, even if you feel better, unless your doctor tells you otherwise. Don't share antibiotics or keep leftovers.
Your doctor decides the right dose for you and how long to take it.
Your doctor decides the right dose for you. Follow their instructions and the label.
Common Side Effects
Diarrhoea
And tummy pain.
Nausea
And vomiting.
Hearing changes
Rarely.
Interactions
Heart rhythm medicines
Can affect heart rhythm.
Antacids
Take at a different time.
Critical Warnings
Heart rhythm
Can cause abnormal rhythm in people at risk.
Severe or bloody diarrhoea
Can be a sign of a serious bowel infection. Contact a doctor.
Severe allergic reaction
Black Box Warning: Swelling of the face or throat, difficulty breathing or a widespread rash: get emergency help.
Antibiotic resistance
Using antibiotics when they aren't needed makes them less effective for everyone.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Azithromycin: drug information(opens in a new tab) · MedlinePlus, US National Library of Medicine
- Azithromycin: antibiotic to treat bacterial infections(opens in a new tab) · NHS