How does this medication work? What will it do for me?

Azithromycin belongs to the family of medications known as macrolide antibiotics. It is used to treat certain types of infections that are caused by bacteria. It is most commonly used to treat ear infections (e.g., otitis media), throat infections, lung infections (e.g., pneumonia), and skin infections. It can also be used to prevent mycobacterium avium complex (MAC) infections in people with HIV infection.

Your doctor may have suggested this medication for conditions other than the ones listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are being given this medication, speak to your doctor. Do not stop using this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to use this medication if their doctor has not prescribed it.

What form(s) does this medication come in?

Each dark pink, oval, film-coated, biconvex tablet, engraved "AZ250" on one side and "APO" on the other side contains azithromycin isopropanolate monohydrate equivalent to 250 mg. Nonmedicinal ingredients: colloidal silicon dioxide, croscarmellose sodium, D&C Red No. 30, hydroxyethyl cellulose, magnesium stearate, microcrystalline cellulose, polyethylene glycol, stearic acid, titanium dioxide, and vitamin E.

How should I use this medication?

The recommended adult dose of azithromycin for treatment of lung and skin infections is two 250 mg tablets taken on the first day, followed by one 250 mg tablet taken at the same time each day for 4 more days. The usual dose for prevention of mycobacterium avium complex (MAC) infections in people with HIV infection is 1,200 mg taken once weekly.

The children's dose of azithromycin (liquid suspension) is based on body weight. When used to treat otitis media (middle ear infection) in children, a course of treatment or either 1 day, 3 days or 5 days may be used. The daily dose will vary depending on the number of treatment days. Use an oral syringe to measure each dose of the liquid, as it gives a more accurate measurement than household teaspoons.

Doses of azithromycin for treatment of other conditions vary according to the condition being treated.

Azithromycin may also be given by injection to treat severe pneumonia or pelvic inflammatory disease. It is usually given in a hospital setting by a health professional. Your doctor will determine the appropriate dose of this medication.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones given here, do not change the way that you are taking the medication without consulting your doctor.

Azithromycin must be taken for the recommended duration of treatment, even if you are feeling better. This will reduce the chances of having remaining bacteria grow back.

The medication may be taken with or without food. Taking the medication with food may help to avoid stomach upset.

It is important to take this medication exactly as prescribed by your doctor. Finish all of this medication, even if you start to feel better. If you miss a dose, take it as soon as possible and continue on with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store all forms of this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children. Discard any unused suspension (liquid) after 10 days.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Who should NOT take this medication?

Do not take azithromycin if you:

  • are allergic to azithromycin or any ingredients of the medication
  • are allergic to erythromycin or other macrolide antibiotics (e.g., clarithromycin)
  • have had liver problems caused by taking azithromycin in the past

What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent. The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

  • diarrhea (mild)
  • dizziness
  • headache
  • nausea
  • stomach pain or discomfort
  • vomiting

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

  • fever
  • joint pain
  • signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
  • signs of myasthenia gravis (e.g., muscle weakness, vision changes, difficulty chewing and swallowing)

Stop taking the medication and seek medical attention immediately if any of the following side effects occur:

  • abdominal or stomach cramps or pain (severe)
  • abnormal heart rhythm
  • diarrhea (watery and severe, which may be bloody)
  • signs of a severe allergic reactions (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)
  • symptoms of a severe skin reaction (e.g., blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with fever or discomfort)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.


May 16, 2013

Health Canada has issued new information concerning the use of Zithromax/Zmax SR (azithromycin). To read the full report, visit Health Canada's website at

Antibiotic-associated colitis: This medication, like other antibiotics, may cause a potentially dangerous condition called antibiotic-associated, or pseudomembranous, colitis. Symptoms include severe, watery diarrhea that may be bloody. If you notice these symptoms, stop taking azithromycin and contact your doctor as soon as possible.

Heart conditions: Azithromycin can cause an abnormal heart rhythm and should be avoided by people with certain heart rhythm problems, especially long QT syndrome, congenital QT interval prolongation, and bradycardia (low heart rate). There have been a few reports of long QT syndrome occurring with people taking azithromycin. People who have had irregular heart rhythms caused by other medications in the past should avoid taking azithromycin. It should also be avoided by people with low blood potassium or magnesium levels, and by people taking certain medications used to treat irregular heart rhythms (e.g., quinidine, procainamide, amiodarone, sotalol). If you experience an irregular heartbeat, stop taking this medication and contact your doctor.

Kidney disease: If you have kidney disease or reduced kidney function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Liver disease: The liver is responsible for removing most of the azithromycin from the body. If it is not working properly, there is an increased risk of side effects of the medication. If you have liver disease or reduced liver function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Myasthenia gravis: Myasthenia gravis is a condition that causes specific muscle weakness. Azithromycin may cause the symptoms of myasthenia gravis to flare up. If you have myasthenia gravis, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Overgrowth of organisms: Prolonged or repeated use of azithromycin may result in an overgrowth of bacteria or fungi and organisms that are not killed by the medication. This can cause other infections, such as yeast infections, to develop.

Pregnancy: The safety of azithromycin for use by pregnant women has not been established. This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: It is not known if azithromycin passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and efficacy of azithromycin tablets or suspension have not been established for treating children younger than 6 months of age who have acute otitis media or community-acquired pneumonia.

The safety and efficacy of azithromycin tablets or suspension have not been established for treating children younger than 2 years of age who have throat infections or tonsillitis.

The safety and efficacy of azithromycin injection have not been established for children less than 16 years of age.

What other drugs could interact with this medication?

There may be an interaction between azithromycin and any of the following:

  • alfuzosin
  • amantadine
  • amiodarone
  • anagrelide
  • atazanavir
  • antihistamines (e.g., cetirizine, doxylamine, diphenhydramine, hydroxyzine, loratadine)
  • antipsychotics (e.g., chlorpromazine, clozapine, haloperidol, olanzapine, quetiapine, risperidone)
  • apomorphine
  • atorvastatin
  • "azole" antifungals (e.g., itraconazole, ketoconazole, voriconazole)
  • BCG
  • bosutinib
  • chloral hydrate
  • chloroquine
  • cisapride
  • cyclosporine
  • dasatinib
  • digoxin
  • disopyramide
  • domperidone
  • dronedarone
  • famotidine
  • fingolimod
  • flecainide
  • formoterol
  • galantamine
  • indapamide
  • ivabradine
  • ivermectin
  • lapatinib
  • lithium
  • lopinavir
  • lovastatin
  • macrolide antibiotics (e.g., clarithromycin, erythromycin)
  • maprotiline
  • mefloquine
  • methadone
  • mifepristone
  • mirabegron
  • nelfinavir
  • nilotinib
  • octreotide
  • paliperidone
  • pazopanib
  • pentamidine
  • pimozide
  • procainamide
  • propafenone
  • ritonavir
  • rivaroxaban
  • romidepsin
  • quinidine
  • quinine
  • quinolone antibiotics (e.g., ciprofloxacin, norfloxacin, ofloxacin)
  • rilpivirine
  • ritonavir
  • salmeterol
  • saquinavir
  • selective serotonin reuptake inhibitors SSRIs; e.g., citalopram, duloxetine, fluoxetine, paroxetine, sertraline)
  • serotonin antagonists (anti-emetic medications; e.g., granisetron, ondansetron)
  • simvastatin
  • sodium picosulfate
  • solifenacin
  • sotalol
  • sulfamethoxazole
  • sunitinib
  • tacrolimus
  • tamoxifen
  • tetrabenazine
  • trazodone
  • trimethoprim
  • tricyclic antidepressasnts (e.g., amitriptyline, clomipramine, desipramine, trimipramine)
  • typhoid vaccine
  • vandetanib
  • vemurafenib
  • vardenafil
  • venlafaxine
  • vilanterol
  • warfarin

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

  • stop taking one of the medications,
  • change one of the medications to another,
  • change how you are taking one or both of the medications, or
  • leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.