Zithromax (Azithromycin) Use in Children

How to Use the Antibiotic Safely in Kids

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Zithromax (azithromycin) is an antibiotic commonly used in children to treat bacterial infections, such as ear and sinus infections. Often prescribed in pill form, it can also be delivered in a liquid formulation for children who don't like pills. Depending on the infection your child has, the treatment would typically last anywhere from one to five days.


Though Zithromax is approved for use in children, its safety and effectiveness in kids under the age of 6 months haven't been established. The drug has been approved to treat the following pediatric conditions:

Zithromax is often used off-label for other mild to moderate pediatric infections that are caused by susceptible bacteria including walking pneumonia and pertussis (whooping cough).

Zithromax is generally not used in first-line treatment unless the first-line antibiotic has failed or the child has an allergy to the preferred drug.

Increasing rates of azithromycin resistance mean that the drug is generally reserved for second-line use. For strep throat, penicillin is the preferred agent. Similarly, for ear infections, the American Academy of Pediatrics (AAP) recommends amoxicillin as the first-line drug of choice.


Zithromax is a type of macrolide antibiotic, a group that also includes erythromycin, roxithromycin, and clarithromycin. It is a good choice for children who are allergic to penicillin and can be taken either with or without food, often in a single dose.

Zithromax has also been popular because it has always been a little less expensive than many other brand name antibiotics, even before it became available as a generic.

Zithromax is available in several forms:

  • Zithromax for oral suspension
  • Zithromax Z-Pak, 250 mg tablets (five-day course)
  • Zithromax Tri-Pak, 500 mg tablets (three-day course)
  • Zmax (extended-release formulation)

Zithromax can be stored at room temperature, but keep it away from excessive heat, cold, or moisture. Do not refrigerate or freeze Zithromax, even in liquid form. If given Zithromax in a powder form, mix it with water right before giving your child the dose.


Depending on the condition being treated, your healthcare provider will usually tailor the dose based on your child's height and weight (measured in kilograms, kg). Typical dosages include:

  • Ear infection: Either a single dose (30 mg/kg); a once-daily dose for three days (10 mg/kg/day); or a once-daily dose for five days (starting with 10 mg/kg for the first day and decreasing to 5 mg/kg/day on the next four days)
  • Sinus infections: Once daily for three days (10 mg/kg)
  • Community-acquired pneumonia: Once daily for five days (starting with 10 mg/kg on the first day and decreasing to 5 mg/kg/day on the next four days)
  • Strep throat or tonsillitis: Once daily for five days (12 mg/kg)

If you miss a dose, give it as soon as you remember unless the next dose is within 12 hours. In such a case, skip the dose and give your child the next one as you normally would. Never double up on doses as this can increase the risk of side effects.

Be sure to give Zithromax exactly as prescribed, completing the entire course even if your child feels better. Failure to do so increases the risk of antibiotic resistance, making the drug far less effective the next time your child is ill.

If your child vomits within an hour of taking a one-time dose, you will likely need to get another. Call your pediatrician for guidance.

Side Effects

Common side effects of zithromax
Illustration by Brianna Gilmartin, Verywell

For children taking a five-day course of Zithromax, the most common side effects include:

  • Diarrhea and loose stools
  • Abdominal pain
  • Vomiting
  • Nausea
  • Rash
  • Headache

When prescribed as a one-time dose, there is a greater risk of vomiting or diarrhea. If the side effects are severe or persistent, call your healthcare provider. On rare occasions, a child may experience a severe and potentially life-threatening allergy known as anaphylaxis.

When to Call 911

Call 911 or seek emergency care if your child experiences shortness of breath, wheezing, rapid heart rate, dizziness, vomiting, or swelling of the face, tongue, or throat after taking Zithromax.

Drug Interactions

If your child is taking Zithromax and an antacid such as Tums, Mylanta, or Maalox, you may need to separate the doses by four hours to avoid a drop in the concentration of Zithromax in the blood. Antacids can be taken at the same time if prescribed an extended-release Zmax.

Always advised your pediatrician about any and all drugs your child may be taking, whether pharmaceutical, over-the-counter, nutritional, homeopathic, or traditional.

QT Interval Warning

The U.S. Food and Drug Administration warns that azithromycin can cause changes in the normal electrical activity of the heart, leading to an abnormal heart rhythm condition known as QT interval prolongation. This can cause fast and/or irregular heartbeat, severe dizziness, blurred vision, fainting, and, rarely, death.

Certain factors can increase a child's risk while taking Zithromax:

  • A family history of QT interval prolongation
  • Low blood potassium or magnesium
  • A family history of abnormal heart rhythms (arrhythmias)
  • Use of anti-arrhythmia medications

Call your healthcare provider if your child experiences irregular heartbeats or has a sudden dizziness spell. if there is fainting, take your child to the emergency room even it lasted for only a few seconds.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Pfizer Laboratories. Labeling for ZITHROMAX-azithromycin dihydrate tablet, film coated; ZITHROMAX-azithromycin dihydrate powder, for suspension.

  2. Ovetchkine P, Rieder MJ. Azithromycin use in paediatrics: A practical overview. Paediatr Child Health. 2013;18(6):311-6. doi:10.1093/pch/18.6.311

  3. Lieberthal AS, Carroll AE, Chonmaitree T, et al. The diagnosis and management of acute otitis media. Pediatrics. 2013;131(3):e964-99. doi:10.1542/peds.2012-3488

  4. MedlinePlus. Azithromycin.

  5. U.S. Food & Drug Administration. FDA Drug Safety Communication: Azithromycin (Zithromax or Zmax) and the risk of potentially fatal heart rhythms.