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Medication guide

Azithromycin

Treats selected bacterial infections when appropriate to the diagnosis.

Check the name, strength and form on your own prescription or package.

Brand
Zithromax
Form
Oral macrolide antibiotic
Guidance checked
2026-09-08

About this medication

  • Azithromycin is an antibiotic. It treats infections caused by bacteria.
  • It is used for chest infections such as bronchitis and pneumonia.
  • It is used for throat, skin, and soft-tissue infections.
  • It is used for certain sexually transmitted infections.
  • It can also be used, on a different schedule, to help prevent a serious lung infection in people with advanced HIV.

Treats selected bacterial infections when appropriate to the diagnosis.

How to use it

  • Take this medicine exactly as your healthcare professional tells you. The amount and how often you take it will be on your prescription label.
  • Swallow the tablet with a glass of water. You can take it with or without food.
  • Finish the entire course, even if you feel better after a few days — stopping early can let the infection come back or become harder to treat.
  • If you also take an antacid, take it at a different time than azithromycin, since antacids can reduce how well azithromycin works.

If you miss a dose

  • Take the missed dose as soon as you remember.
  • If it is almost time for your next dose, skip the missed one and go back to your normal schedule.
  • Do not take two doses at the same time to make up for a missed one.

Different infections require different courses. Follow the prescribed regimen.

Pregnancy and breastfeeding

  • Tell your doctor if you are pregnant or planning to become pregnant. Azithromycin should only be used in pregnancy if your doctor feels it is needed.
  • Talk to your doctor before breastfeeding while taking this medicine, since it can pass into breast milk.

Use during pregnancy or breastfeeding requires an individual benefit-risk discussion.

Before you use it

  • Tell your healthcare professional if you have ever had liver problems, especially after taking azithromycin or another antibiotic before.
  • Tell your healthcare professional if you have a heart rhythm problem, a slow heartbeat, or low potassium or magnesium levels.
  • Tell your healthcare professional if you have myasthenia gravis, a condition that causes muscle weakness.
  • This medicine treats bacterial infections only. It will not work for colds, flu, or other viral illnesses.

Important warnings

  • Azithromycin can affect your heart rhythm and, rarely, cause a fast or irregular heartbeat that can be dangerous.
  • Serious allergic reactions, including swelling of the face or throat and trouble breathing, can happen. In some cases symptoms have come back after initial treatment, so keep watching for symptoms even after you feel better.
  • Rare but serious skin reactions can occur, including severe rash, blistering, or peeling skin.
  • Rare but serious liver problems, including liver failure, have happened with this medicine.
  • Severe diarrhea caused by a serious bowel infection can develop, sometimes even weeks after you finish the medicine.
  • Rarely, this medicine can affect your blood cells, kidneys, hearing, or nervous system, or worsen myasthenia gravis.

Avoid macrolide allergy or previous azithromycin-related liver injury. Review heart rhythm problems and myasthenia gravis.

Possible side effects

  • Diarrhea or loose stools.
  • Nausea.
  • Stomach pain.
  • Vomiting.
  • Indigestion.
  • Headache.
  • Dizziness.
  • Vaginal yeast infection.
  • Skin rash or itching.
  • Reduced appetite.

Nausea, abdominal pain and diarrhoea.

When to get help

When to get emergency help

  • A fast, pounding, or irregular heartbeat, or fainting.
  • Swelling of the face, lips, tongue, or throat, or trouble breathing or swallowing.
  • Yellowing of the skin or eyes, dark urine, or severe stomach pain, which can be signs of a liver problem.
  • A severe rash with blistering, peeling skin, or sores in the mouth.
  • Severe or bloody diarrhea, especially if it starts weeks after finishing the medicine.
  • Sudden muscle weakness or difficulty breathing.

When to contact a healthcare professional

  • If side effects bother you or do not go away.
  • If your symptoms do not improve after finishing the full course.
  • If you notice hearing changes.
  • If you develop new confusion, agitation, or seizures.

Fainting, palpitations, jaundice, severe rash or persistent diarrhoea require assessment.

Other medicines and products

  • Tell the Care365 care team about all medicines you take, including migraine medicines called ergot derivatives, which should not be combined with azithromycin.
  • Blood thinners such as warfarin can be affected by azithromycin — your doctor may need to check your blood more often.
  • Certain heart, cholesterol, seizure, and immune-suppressing medicines can interact with azithromycin, so make sure the Care365 care team has a full list of what you take.
  • Space antacids at least two hours apart from your dose.
  • You can take azithromycin with or without food.

Review QT-prolonging medicines, warfarin, ergot medicines and antacid timing.

Missed doses, storage and accidental exposure

  • Store tablets at room temperature.
  • Keep out of reach of children.
  • Return any leftover medicine to your pharmacy — do not save it for a future illness.

Follow your own product’s missed-dose instructions. If you are unsure, ask the Care365 clinical team before taking an extra dose. Contraceptives, injections and modified-release medicines may need a specific plan.

Keep the original packaging and follow its storage, expiry and disposal instructions. Keep medicines away from children and pets. Ask about refrigeration, after-opening limits and safe sharps disposal when relevant.

For suspected overdose or accidental swallowing, contact poison control or urgent medical care promptly. Call emergency services for breathing difficulty, collapse or a seizure.

Key points to remember

  • Complete the full course of antibiotic, even if you feel better early.
  • Tell the Care365 care team about any past allergic reactions to antibiotics, especially other macrolide antibiotics like erythromycin.
  • Do not share this medicine with anyone else.
  • Contact the Care365 care team if symptoms return after you finish treatment.

These practical points come from the Pharmasist patient handout for the same product monograph cited by this guide.

References and product information

Sources checked .

Sources checked 2026-09-08. Safety sections are highlights; consult the full product information for complete warnings and instructions.

Check the Canadian Drug Product Database by product name or DIN for current product information.

This is a plain-language guide, not the complete monograph. Match the name, strength and form on your package before using product-specific directions.

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