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Antibiotic (macrolide)

Azithromycin: uses, side effects & precautions

Also known as Zithromax, Z-Pak, Azithrocin.

This information is for general guidance only and does not constitute medical advice. Always consult a qualified healthcare professional for personal medical concerns. In an emergency, call your local emergency number.

What it is used for

  • Chest and respiratory infections such as some pneumonia and bronchitis
  • Ear, throat and sinus infections
  • Some sexually transmitted infections such as chlamydia
  • Some skin infections
  • Certain travel-related and gut infections

How it works

Azithromycin is a macrolide antibiotic. It blocks bacteria from making the proteins they need to grow and multiply, which stops the infection from spreading and helps the body clear it. It does not work against viruses.

How it is taken

Comes as tablets, capsules, a liquid (oral suspension), eye drops, and an injection in hospital. Take it exactly as your doctor or pharmacist directs and follow the label. It is often given as a short course. Take the full course as advised even if you feel better.

No doses here on purpose. The right strength and schedule depend on you — only a doctor or pharmacist should set them. Always follow your prescription and the label.

Common side effects

  • Nausea
  • Diarrhoea
  • Stomach pain
  • Vomiting
  • Headache
  • Changes in taste

Serious effects — get help

  • Severe allergic reaction with swelling or breathing difficulty
  • An irregular or fast heartbeat or fainting (it can affect heart rhythm)
  • Severe, persistent or bloody diarrhoea
  • Yellowing of the skin or eyes (possible liver problem)
  • Severe blistering or peeling skin reactions

If a reaction is severe — for example trouble breathing, swelling of the face or throat, or collapse — go to the nearest emergency room now or call your local emergency number. Do not wait for an online consultation.

Interactions to watch

  • Antacids containing aluminium or magnesium (separate the timing)
  • Blood thinners such as warfarin
  • Other medicines that affect heart rhythm
  • Some statins
  • Ergot-type migraine medicines
  • Certain medicines for irregular heartbeat

Who should take care

  • Tell your clinician about any allergy to macrolide antibiotics
  • Tell your clinician if you have heart rhythm problems or a family history of them
  • Tell your clinician if you have liver or kidney problems
  • Tell your clinician if you have myasthenia gravis
  • Discuss pregnancy or breastfeeding with your doctor or pharmacist

Frequently asked questions

Why is azithromycin often a short course?
It stays active in the body for a relatively long time, so clinicians may prescribe a short course. Always follow the exact directions you are given.
Can it affect my heart?
In some people it can change the heart's rhythm. Tell your clinician about any heart conditions or fainting, and seek urgent care for a fast, irregular heartbeat.
Can I take it with antacids?
Some antacids can reduce how well it is absorbed. Your pharmacist can advise on spacing the doses apart.
Does it treat chlamydia?
It is one of the antibiotics used for chlamydia. Take it exactly as directed and follow any advice about testing and partner treatment from your clinician.
Is Azithromycin safe to take?
For most people it is safe when taken exactly as a doctor or pharmacist advises and as printed on the label. Tell your clinician about your other medicines and health conditions, and seek urgent care for any serious reaction.

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