Health Library

Azithromycin (By mouth)

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

Treats infections. This medicine is a macrolide antibiotic.

Brand Name(s):

Zithromax, Zithromax Tri-Pak, Zithromax Z-Pak

When This Medicine Should Not Be Used:

How to Use This Medicine:

Capsule, Liquid, Packet, Powder, Tablet

• Your doctor will tell you how much medicine to use. Do not use more than directed.
• Take all of the medicine in your prescription to clear up your infection, even if you feel better after the first few doses.
• Multiple dose (Zithromax® oral liquid or tablets):
  • You may take this medicine with or without food.
  • Shake the bottle well before you measure the medicine. Measure the oral liquid medicine with a marked measuring spoon, oral syringe, or medicine cup.
• Single dose (Zmax® extended-release oral liquid or powder):
  • Liquid:
    • Take this medicine on an empty stomach at least 1 hour before you eat, or 2 hours after you eat.
    • Call your doctor right away if you vomit within 1 hour after you take the medicine.
    • You must take the liquid within 12 hours after the pharmacist gives it to you.
    • Shake the bottle well before you measure the medicine. Measure your dose with a marked measuring spoon, cup, or syringe.
  • 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 of water into the same glass, and drink the remaining medicine.
• Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.
• Missed dose: If you are taking multiple doses, take the dose as soon as you remember. If it is almost time for your next dose, wait until then to take a regular dose. Do not use extra medicine to make up for a missed dose.
• Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
• Extended-release oral liquid: Do not refrigerate or freeze.
• Oral liquid for 1 dose only: Store at room temperature. Do not store in the refrigerator or allow the medicine to freeze.
• Oral liquid for multiple doses: Store at room temperature or in the refrigerator. Use it within 10 days of filling the prescription.

Drugs and Foods to Avoid:

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

• Some medicines can affect how azithromycin works. Tell your doctor if you are also using any of the following:
  • Colchicine, cyclosporine, digoxin, nelfinavir, phenytoin
  • Blood thinner (including warfarin)
  • Ergot medicine
  • Medicine for a heart rhythm problem (including amiodarone, dofetilide, procainamide, quinidine, sotalol)
• Zithromax® for multiple doses: Do not take an antacid that contains magnesium or aluminum at the same time you take Zithromax®. An antacid will affect how the medicine works. Antacids will not affect Zmax® for single dose.

Warnings While Using This Medicine:

• Tell your doctor if you are pregnant or breastfeeding, or if you have kidney disease, liver disease, heart disease, heart rhythm problems, heart failure, or myasthenia gravis. Tell your doctor if anyone in your family has heart rhythm problems.
• This medicine may cause the following problems:
  • Serious skin reactions, including Stevens-Johnson syndrome, acute generalized exanthematous pustulosis, toxic epidermal necrolysis, and drug reaction with eosinophilia and systemic symptoms (DRESS)
  • Liver problems
  • Infantile hypertrophic pyloric stenosis
  • Heart rhythm problems, including QT prolongation
  • Increased risk of serious heart or blood vessel problems
• This medicine can cause diarrhea. Call your doctor if the diarrhea becomes severe, does not stop, or is bloody. Do not take any medicine to stop diarrhea until you have talked to your doctor. Diarrhea can occur 2 months or more after you stop taking this medicine. It may occur 2 months or more after you stop using this medicine.
• Call your doctor if your symptoms do not improve or if they get worse.
• Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.
• Keep all medicine out of the reach of children. Never share your medicine with anyone.

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
• Dark urine, pale stools, nausea, vomiting, loss of appetite, stomach pain, yellow skin or eyes
• Fainting, dizziness, lightheadedness
• Fast, pounding, or uneven heartbeat, blurred vision, chest pain, trouble breathing, tiredness or weakness
• Feeling irritable or vomits after feeding (in babies)
• Severe diarrhea that may contain blood, stomach cramps, fever

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

• Mild diarrhea, nausea, vomiting, stomach pain

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

Last Updated: 9/6/2024