Azithromycin (By mouth)


Azithromycin (ay-zith-roe-MYE-sin)

Treats bacterial infections. This medicine is a macrolide antibiotic.

Brand Name(s)

Zithromax, Zmax, Zithromax Z-Pak, Zithromax Tri-Pak, Zithromax Z Pack

There may be other brand names for this medicine.

When This Medicine Should Not Be Used

Do not use this medicine if you have had an allergic reaction to azithromycin, clarithromycin (Biaxin®), erythromycin (Ery-tab®), or telithromycin (Ketek®). Do not use this medicine if you have a history of liver disease.

How to Use This Medicine

Capsule, Liquid, Packet, Powder, Tablet

  • Your doctor will tell you how much of this medicine to use and how often. Do not use more medicine or use it more often than your doctor tells you to.
  • This medicine comes with patient instructions. Read and follow these instructions carefully. Ask your doctor or pharmacist if you have any questions.
  • Multiple dose (Zithromax® oral liquid or tablets):
    • You may take this medicine with or without food.
    • Keep using this medicine for the full treatment time, even if you feel better after the first few doses. Your infection may not clear up if you stop using the medicine too soon.
    • Measure the oral liquid medicine with a marked measuring spoon, oral syringe, or medicine cup.
    • Shake the bottle well before you measure the medicine.
  • Single dose (Zmax® extended-release oral liquid or powder):
    • Liquid:
      • Take this medicine on an empty stomach. Take your dose at least 1 hour before you eat, or 2 hours after you eat.
      • Call your doctor right away if you vomit within 1 hour of taking the medicine to see if you need more medicine.
      • You must take the liquid within 12 hours after it has been mixed with water.
      • Shake the bottle well before you measure the medicine. Measure your dose with a marked measuring spoon, cup, or syringe if you only need to use part of the liquid in the bottle.
    • Powder:
      • Open 1 packet and pour all of the medicine into a glass with about 2 ounces (¼ cup) of water. Mix well and drink the medicine right away. Pour another 2 ounces (¼ cup) of water into the same glass, and drink the remaining medicine.

If a dose is missed:

  • This medicine is sometimes given as a single dose. If you are taking multiple doses and you miss a dose or forget to use your medicine, use it as soon as you can. If it is almost time for your next dose, wait until then to use the medicine and skip the missed dose. Do not use extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
  • Oral liquid: You may store the oral liquid at room temperature or in the refrigerator. Use it within 10 days of filling the prescription. Throw away any leftover medicine when you are finished with your treatment.
  • Extended-release oral liquid: Do not refrigerate or freeze the extended-release oral liquid. Throw away any unused liquid.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
  • Keep all medicine away from children and never share your medicine with anyone.

Drugs and Foods to Avoid

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Make sure your doctor knows if you are also using atorvastatin (Lipitor®), cetirizine (Zyrtec®), cyclosporine (Gengraf®, Neoral®, Sandimmune®), digitalis, digoxin (Digitek®, Lanoxin®), fluconazole (Diflucan®), midazolam (Versed®), rifabutin (Mycobutin®), sildenafil (Viagra®), theophylline (Theo-Dur®), or triazolam (Halcion®). Tell your doctor if you are also using a blood thinner such as warfarin (Coumadin®, Jantoven®), a sulfa drug (such as trimethoprim/sulfamethoxazole, Bactrim®, Septra®), or any ergot medicines (such as ergotamine, Cafergot®, Ergomar®, Wigraine®). Make sure your doctor knows if you are also using a medicine for HIV or AIDS (such as atazanavir, darunavir, didanosine, efavirenz, emtricitabine, lamivudine, lopinavir, raltegravir, ritonavir, tenofovir, zidovudine, Atripla®, Crixivan®, Emtriva®, Epzicom®, Isentress®, Kaletra®, Norvir®, Truvada®), medicine for seizures (such as carbamazepine, hexobarbital, phenytoin, Carbartrol®, Dilantin®, or Tegretol®), or medicine for heart rhythm problem (such as amiodarone, dofetilide, quinidine, procainamide, sotalol, Betapace®, Cardioquin®, Cordarone®, Procanbid®, Quinaglute®, or Tikosyn®).
  • Some medicines may keep azithromycin from working properly. Do not take aluminum- or magnesium-containing antacids with Zithromax®. However, you can take antacids with Zmax®.

Warnings While Using This Medicine

  • Make sure your doctor knows if you are pregnant or breastfeeding, or if you have kidney disease, liver disease, cystic fibrosis, heart disease, heart rhythm problems (such as QT prolongation, slow heartbeat), low potassium or magnesium in the blood, myasthenia gravis (severe muscle weakness), or problems with your immune system. Tell your doctor if you have had problems with your spleen.
  • Serious skin reactions can occur. Stop using this medicine and tell your doctor right away if you have blistering, peeling, or loosening of the skin, red skin lesions, severe acne or skin rash, sores or ulcers on the skin, or fever or chills while you are using this medicine.
  • Stop using this medicine and tell your doctor right away if you have dark-colored urine or pale stools, nausea, vomiting, loss of appetite, pain in your upper stomach, or yellow skin or eyes. These could be symptoms of a serious liver problem.
  • If you have severe diarrhea, ask your doctor before taking any medicine to stop the diarrhea.It may occur 2 months or more after you stop using this medicine.
  • Contact your doctor right away if you have any changes to your heart rhythm. You might feel dizzy or faint, or you might have a fast, pounding, or uneven heartbeat. Make sure your doctor knows if you or anyone in your family has ever had a heart rhythm problem such as QT prolongation.
  • This medicine needs time to work, so you may not feel better right away.
  • Only use this medicine as directed by your doctor to treat a bacterial infection. This medicine will not treat viral infections such as the flu or the common cold.

Possible Side Effects While Using This Medicine

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Blistering, peeling, red skin rash
  • Change in how much or how often you urinate
  • Chest pain, fast or pounding heartbeat
  • Dark-colored urine, pale stools, nausea, vomiting, loss of appetite, pain in your upper stomach, yellow skin or eyes
  • Double vision, muscle weakness
  • Severe diarrhea that may contain blood, black stools
  • Unusual tiredness or weakness

If you notice these less serious side effects, talk with your doctor:

  • Headache
  • Mild stomach pain, diarrhea, gas, vomiting, upset stomach

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Version Info

  • Last Reviewed on 06/12/2013

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This page was last updated: July 31, 2013

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