Sounds like 'ay-ZITH-ro-MYE-sin'

Azithromycin is an antibiotic used to treat different infections caused by bacteria. Find out how to take it safely and possible side effects. Azithromycin is commonly called Zithromax.

Type of medicine Also called
  • Antibiotic
  • Belongs to a group of antibiotics known as macrolides
  • Zithromax®
  • Apo-Azithromycin®

What is azithromycin?

Azithromycin is an antibiotic used to treat different infections caused by bacteria such as whooping cough, infections of the ear, skin and genitals such as gonorrhoea or chlamydia. Azithromycin is also used to prevent infections in people with cystic fibrosis. It works by killing or stopping the growth of bacteria (bugs) that cause the infection. It is not effective against infections caused by viruses. 


In Aotearoa New Zealand azithromycin is available as tablets (250mg and 500mg)  and liquid.

  • The dose of azithromycin will be different for different people depending on the type of infection and your age. 
  • The usual dose in adults is 250 mg or 500 mg once a day. Your doctor will advise you on the dose to take and how long to take azithromycin for (usually 3 to 5 days). 
    For genital infections (gonorrhoea and chlamydia) azithromycin is taken for one day as a single 1 gram dose (2 x 500 milligram tablets).
  • The dose for children will depend on their body weight.
  • Always take your azithromycin exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much to take, how often to take it, and any special instructions.

How to take azithromycin

  • Timing of your doses: Azithromycin is usually taken once a day. Take your dose at about the same time each day. You can take azithromycin with or without food. Swallow your tablet with a drink of water.
  • Missed dose: If you forget to take azithromycin, take it as soon as you remember. But, if it is nearly time for your next dose, just take the next dose at the right time. Do not take double the dose.
  • Finish the course. Keep taking azithromycin until you finish the course, or for as long as your doctor or pharmacist tells you to.

For information on how to give azithromycin to children, see azithromycin information for parents and carers.

Things to consider while you are taking azithromycin

  • Azithromycin may interact with some medicines, including warfarin, and herbal supplements, so check with your doctor or pharmacist before you start taking azithromycin.
  • Azithromycin does not have direct interactions with alcohol. This means that most people could have the occasional drink while taking it without any serious problems. However, if azithromycin makes you feel sick (nausea) or dizzy, do not drink alcohol as it will make you feel worse.

Possible side effects 

Like all medicines azithromycin can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Side effects What should I do?
  • Stomach upset
  • Feeling bloated, gas in the tummy
  • Tummy ache
  • Take with food.
  • Tell your doctor if these bother you.
  • Feeling sick, nausea or mild diarrhoea (runny stools)
  • Headache
  • Tell your doctor if these bother you.
  • If you are also taking the oral contraceptive pill and have been vomiting or have diarrhoea, ask your doctor or pharmacist for advice.
  • Vaginal itch or discharge (thrush)
  • Small white sores in the mouth (oral thrush)
  • Tell your doctor.
  • Fainting or feeling like your heart is beating too fast
  • Signs of problems with your liver such as yellowing of the skin or eyes, dark urine, pain in the tummy
  • Tell your doctor immediately or ring Healthiine 0800 611 116.
For more information on side effects, see the Medsafe consumer information leaflets Zithromax and Apo-Azithromycin.

Did you know that you can report a side effect from a medicine to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product.

Learn more

Azithromycin NZ Formulary
Azithromycin (for chlamydia) NZ Formulary
Zithromax Medsafe Consumer Information Sheet, NZ


  1. Azithromycin NZ Formulary
  2. Check INR after starting roxithromycin for patients on warfarin Medsafe, NZ, 2015
  3. Upfront: Azithromycin: use it wisely BPAC, NZ, April 2014
  4. News and updates: Update on azithromycin BPAC, NZ, November 2012
Credits: Sandra Ponen, Pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 24 Mar 2019