Zithromax (Azithromycin) Antibiotic Use in Children

Checking fever
baona/E+/Getty Images

Zithromax (azithromycin) is an antibiotic that is commonly used in children for a variety of reasons, such as ear and sinus infections. Often prescribed as a liquid, it is also available in pill form; you've likely taken a five-day Z-Pak yourself a time or two. Its quick effectiveness (courses run from one to five days) and one-dose-a-day convenience make it a good choice for children who don't like to take medicine in particular. 


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

  • Acute otitis media (ear infections)
  • Acute bacterial sinusitis (sinus infection)
  • Community-acquired pneumonia
  • Pharyngitis or tonsillitis caused by Streptococcus pyrogens (strep throat)

Keep in mind that Zithromax is not considered to be a first-line antibiotic. For example, penicillin should usually be used for strep throat unless a child is allergic to it, in which case Zithromax would be appropriate. Similarly, for ear infections, the American Academy of Pediatrics (AAP) recommends Amoxil (amoxicillin) as the first-line drug. The reason for this is that Zithromax has been associated with bacterial resistance, most notably from the bacterium that causes pneumonia.

Zithromax is often used off-label for other mild to moderate pediatric infections that are caused by susceptible bacteria including cat-scratch disease, chronic bronchitis with a secondary bacterial infection, walking pneumonia, and pertussis, commonly known as whooping cough.


Zithromax is a type of macrolide antibiotic and it works by stopping bacteria growth. It's a good choice for children who are allergic to penicillin and it can be taken either with or without food, usually just once a day. 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 these forms:

  • Zithromax for oral suspension (liquid used primarily for children)
  • Zithromax Z-Pak, 250mg tablets (five-day course)
  • Zithromax Tri-Pak, 500mg tablets (three-day course)

Zithromax for oral suspension is recommended for children in specific dosages that depend on weight. Your doctor may prescribe a different dose for your child, however, so be sure to follow the instructions you're given. Typical dosages include:

  • For ear infections: Either a large one-time dose (30mg/kg), once a day for three days (10mg/kg/day), or once a day for five days starting with 10mg/kg on the first day and decreasing to 5mg/kg/day on the next four days
  • For sinus infections: 10mg/kg/day once a day for three days
  • For community-acquired pneumonia: Once a day for five days starting with 10/mg/kg on the first day and decreasing to 5/mg/kg/day on the next four days
  • For pharyngitis or tonsillitis: 12/mg/kg/day once a day for five days

Your child should start to feel better during the first few days after starting Zithromax. Remember that even though your child might only take Zithromax for five days, it continues to work for up to 10 days.

Be sure to give your child Zithromax exactly the way your doctor has prescribed. Even if your child starts to feel better, have him or her finish all the medicine because otherwise, the infection may not completely clear up.

Side Effects

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 children take the larger one-time dose, potential side effects are the same, but the chance of having vomiting and/or diarrhea is higher. If your child experiences any of these side effects and they're bothersome and don't go away or they're severe, contact your doctor.

There are some rare but serious side effects that Zithromax may cause. If your child has any of these, contact your doctor or get emergency help right away. Potential serious side effects include:

  • Dizziness
  • Fast or irregular heartbeat
  • Fainting
  • Blisters
  • Peeling skin
  • Sores that are filled with pus, fever, and skin swelling
  • Difficulty breathing
  • Hives
  • Itching
  • Severe diarrhea
  • Hoarseness
  • Yellowish tinge to skin and/or eyes
  • Fatigue
  • Abdominal pain

Interactions and Warnings

Talk to your pediatrician and pharmacist about possible drug interactions if your child is taking other medications. In particular, if your child is simultaneously taking Zithromax and an antacid that contains aluminum hydroxide or magnesium hydroxide, such as Tums, Mylanta, or Maalox, ask about the optimal timing for both medications, as the antacid can decrease the antibiotic's effectiveness. However, if your child is on the extended-release form of Zithromax, antacids can be taken at any time.

Like other medications, Zithromax can cause allergic reactions, though this is rare. Children with a known hypersensitivity or allergy to azithromycin, erythromycin, or any other macrolide antibiotic should not take it.

There is also a warning from the U.S. Food and Drug Administration (FDA) that azithromycin can cause changes in the normal electrical activity of the heart, which can lead to an irregular heart rhythm known as QT interval prolongation. This condition can cause a fast and/or irregular heartbeat, severe dizziness, fainting, and, rarely, death.

Your child may be at a higher risk of QT interval prolongation while taking Zithromax if any of these apply to him or her:

  • A personal or family history of QT interval prolongation
  • Low blood levels of potassium or magnesium
  • A personal or family history of a fast, slow, or irregular heart rate
  • Use of certain medications to treat abnormal heart rhythms (arrhythmias)

Practical Tips

Many parents share common questions about giving their child Zithromax. These suggestions may help you as you help your child get better:

  • If you forget to give your child a dose, give it to him or her as soon as you remember unless the next dose will be taken within 12 hours. In this case, skip the missed dose and give your child the next one as you normally would. Don't double up on doses as this can increase side effects and may cause an overdose.
  • It's very convenient if your child can take it, but the big downside of the one-time dose of Zithromax is that if your child vomits within an hour after taking the dose, you will likely need to get another one. Call your doctor for guidance.
  • Store the medication in the container it came in at room temperature and away from heat and moisture. Don't refrigerate or freeze it, even if you have the liquid form, and properly discard any remaining medication after you're finished with it.
  • If you're using liquid Zithromax, be sure to shake it well before you measure it out in the appropriate dosage for your child. If you get Zithromax in a powder form, mix it with water just before you plan to give your child a dose and use it immediately.
    Was this page helpful?
    View Article Sources