💊 Amoxicillin Pediatric Dosing Reference

Amoxicillin is the most prescribed antibiotic for children, used for ear infections, strep throat, pneumonia, and sinus infections. Pediatric dosing is weight-based: milligrams per kilogram per day, split into two or three doses. The standard label range is 45 mg/kg/day, with 80 to 90 mg/kg/day for tougher infections like drug-resistant ear infections.

This page shows those published label ranges for a given weight as an educational reference. It is not a prescription, and it does not replace the prescriber: the right regimen depends on the infection, the child's history, and local resistance patterns.

How to use this reference

Enter the child's weight in kilograms. The tool displays the standard and high-dose daily ranges from the FDA label, split into twice-daily doses.

The label regimens

The FDA label for amoxicillin in children describes weight-based daily totals divided every 8 or 12 hours, with higher ranges for infections where resistant pneumococcus is a concern.

Suspensions come in set concentrations (commonly 250 mg/5 mL or 400 mg/5 mL), so the milliliter amount on the syringe is what parents actually measure. Always use the dosing syringe from the pharmacy, never a kitchen spoon: a "teaspoon" can vary by 50 percent.

Worked example

An 18 kg child (about 40 lb) with an ear infection. The standard range is 18 x 45 = 810 mg per day, or 405 mg twice daily. The high-dose range is 18 x 80 to 18 x 90 = 1,440 to 1,620 mg per day, or 720 to 810 mg twice daily.

With a 400 mg/5 mL suspension, the standard 405 mg dose measures just over 5 mL twice daily. Notice how the high-dose regimen roughly doubles the volume: this is why confirming which regimen the doctor intended matters more than the arithmetic.

Safety points parents miss

Allergy: true penicillin allergy (hives, swelling, breathing trouble) is a hard stop; rashes need a call, not a next dose. Duration: finish the full course even when the child feels better; stopping early breeds resistance. Diarrhea: common and usually mild, but bloody or severe diarrhea needs a call.

Interactions: tell the prescriber about other medicines, and note that amoxicillin can reduce the reliability of some lab tests. For other OTC references, see our Benadryl dosing guide and Aleve label guide, and keep hydration up during fevers.

When to call the pediatrician

Call if there is any sign of allergy, if fever persists beyond 48 to 72 hours on the antibiotic, if the child cannot keep doses down, or if symptoms worsen instead of improving. Dosing questions, including "the pharmacy label says something different from what I expected," are always worth a call: pharmacists would rather answer than correct.

Keep a simple log: date, time, dose given, and temperature. It takes thirty seconds and turns vague worry ("I think we missed one") into answerable questions at the follow-up visit.

Why weight, not age, sets the dose

Children of the same age can differ in weight by 50 percent or more, which is why pediatric dosing abandoned age bands for most drugs. A 4-year-old at 14 kg and one at 22 kg need meaningfully different amounts: 630 mg versus 990 mg per day at the standard 45 mg/kg rate. Age-based dosing would underdose one and overdose the other.

This is also why the pharmacy asks for a current weight at every visit and why parents should re-weigh before a new prescription rather than reusing last year's dose. Growth is the whole point of pediatrics, and doses must grow with the child.

Finishing the course: resistance explained

Stopping antibiotics early feels logical once the child is better, but it selects for resistance. The first days kill the weakest bacteria; the remaining days kill the hardiest. Quit early and the survivors, the ones least affected by the drug, repopulate. Repeat that across millions of prescriptions and resistant strains spread.

The full course also prevents relapse of the original infection, which then needs stronger antibiotics. If side effects make finishing hard, call the pediatrician for options rather than improvising: sometimes the formulation, timing, or probiotic support can be adjusted, and sometimes the drug itself needs switching.

Storing liquid amoxicillin correctly

Reconstituted amoxicillin suspension keeps for 14 days, refrigerated, and then must be discarded even if doses remain. Room-temperature storage shortens potency, and freezing destroys it. Shake well before every dose: the drug settles, and the first unshaken pour can be half-strength while the last is double.

Write the discard date on the bottle the day the pharmacy mixes it, and keep the syringe with the bottle, not in a drawer. These small habits prevent the two classic failures: an ineffective final week and a frantic refill call on day 12.

For informational purposes only, not medical advice. Consult a healthcare professional.