Health & Fitness

Azithromycin Pediatric Dose Calculator

Calculate weight-based azithromycin doses for children for common infections including ear infections, pneumonia, and strep throat. Always confirm with your prescribing doctor or pharmacist.

⚕️ Medical disclaimer: This is an educational reference tool only. Azithromycin requires a prescription. Dose and duration must be confirmed by a qualified healthcare professional based on the child's clinical situation, renal function, and other medications. Never self-prescribe antibiotics.
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Azithromycin dose
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Weight (kg)—
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NoteConfirm with prescribing doctor. Take with food if GI upset occurs.

Azithromycin in pediatric infections

Azithromycin belongs to the macrolide class of antibiotics and is widely used in pediatric practice for its convenient once-daily dosing, short course duration, and effectiveness against a broad range of bacteria including atypical organisms that cause "walking pneumonia."

Its long half-life is one of its most clinically useful features. Because the drug concentrates in tissues and white blood cells, a 5-day course achieves antibiotic concentrations that persist for up to 10 days after the last dose. This is why azithromycin is as effective as longer courses of other antibiotics for the same infections.

For children, azithromycin is available as an oral suspension (liquid) which is convenient for younger children who cannot swallow tablets. The suspension is typically available in concentrations of 100 mg/5 mL or 200 mg/5 mL — it is essential to use the correct concentration when measuring doses at home.

Pediatric dosing is calculated on a mg/kg basis, with the standard protocol being 10 mg/kg on day 1 (loading dose), followed by 5 mg/kg once daily for days 2–5. Adult maximum doses cap the pediatric calculation for older or larger children.

Reference: CDC antibiotic guidance — pediatric outpatient treatment recommendations.

Dosing formula

Standard 5-day course (pneumonia, pharyngitis, skin): Day 1: 10 mg/kg once (max 500 mg) Days 2–5: 5 mg/kg once daily (max 250 mg/day) Total course: 10 + (5×4) = 30 mg/kg Otitis media (single-dose option): 30 mg/kg as a single dose (max 1500 mg) OR 10 mg/kg/day for 3 days (max 500 mg/day) Volume calculation (200 mg/5 mL suspension): Volume (mL) = Dose (mg) ÷ 40 mg/mL

Frequently asked questions

  • For most infections, the standard pediatric azithromycin dose is 10 mg/kg on day 1, followed by 5 mg/kg once daily on days 2–5. For otitis media (ear infections), a single 30 mg/kg dose or a 3-day course of 10 mg/kg/day is sometimes used. Maximum doses are typically capped at adult doses (500 mg day 1, 250 mg days 2–5). Always follow your prescribing doctor's specific instructions.
  • Azithromycin is used in children for: community-acquired pneumonia, otitis media (middle ear infections), pharyngitis/tonsillitis (strep throat in penicillin-allergic patients), sinusitis, Chlamydia infections in adolescents, pertussis (whooping cough) exposure prophylaxis, and Mycobacterium avium complex (MAC) in immunocompromised children. It is a broad-spectrum macrolide antibiotic effective against many bacteria.
  • Amoxicillin is a penicillin-type antibiotic and the first-line treatment for many pediatric infections including strep throat and ear infections. Azithromycin (a macrolide) is used as an alternative when a child is allergic to penicillin, when amoxicillin has failed, or for specific organisms that azithromycin covers better (like Mycoplasma pneumoniae, which causes walking pneumonia). Azithromycin has a longer half-life, allowing for once-daily dosing and shorter courses.
  • Azithromycin has an unusually long half-life of approximately 68 hours — significantly longer than most antibiotics. This is why a 5-day course provides therapeutic antibiotic concentrations in tissues for about 10 days. The drug concentrates in cells and tissues rather than blood, which is why blood levels fall quickly after dosing but tissue levels remain effective. This property makes once-daily dosing effective despite the short course.
  • Yes. The most common side effects are gastrointestinal: nausea, vomiting, abdominal pain, and diarrhea. These are more common when azithromycin is taken on an empty stomach. Serious but rare side effects include liver problems (rare), hearing loss (at high doses), and cardiac arrhythmia (QT prolongation) — particularly relevant in children with heart conditions or those taking other medications. Contact your doctor if your child develops severe abdominal pain, jaundice, or an irregular heartbeat.
  • For most children, taking azithromycin with food reduces stomach upset. However, for some tablet formulations, food can reduce absorption by about 50% — this matters more for older children and adolescents taking tablets. The oral suspension (liquid) form is not affected by food. Check the product labeling or ask your pharmacist, and be consistent with whether you give it with or without food throughout the course.
  • If your child vomits within 30 minutes of taking a dose, most guidelines suggest repeating the dose since drug absorption will have been minimal. If they vomit 30–60 minutes after taking it, roughly half the dose may have been absorbed — use clinical judgment (how sick the child is, how important the antibiotic is) and consult your pharmacist or doctor about whether to repeat. Do not repeat a dose if it was taken more than an hour ago.
  • Azithromycin can treat strep throat (Group A Streptococcus) in children who are allergic to penicillin, but it is not the first-line treatment because resistance rates to macrolides (including azithromycin) in Group A strep are rising — currently around 5–10% in many regions. Penicillin or amoxicillin remain the drugs of choice for strep throat. If azithromycin is used, a throat culture or rapid strep test should confirm the diagnosis and ideally sensitivity.