How this instrument works
Every figure below comes from the FDA-approved prescribing information for naproxen oral suspension, sold under the brand Naprosyn, not from the Aleve box on a store shelf. The over-the-counter label has no valid self-care dose for a child under 12 — its own directions say to ask a doctor for that entire age group. The numbers this calculator works out are a prescription reference, used only when a physician has specifically prescribed naproxen for a diagnosed pediatric condition and needs the arithmetic behind a total daily dose spelled out. Never give a child naproxen at these or any doses without it being specifically prescribed and directed by their doctor. If you suspect an overdose or are unsure what was already given, call Poison Control at 1-800-222-1222 (US) or emergency services immediately, and always measure a liquid dose with the calibrated device the pharmacy provides — never a household spoon.
The prescribing information sets a total daily dose near 10 mg per kilogram, split into two roughly equal doses given about twelve hours apart, with an absolute ceiling of 15 mg per kilogram per day that a prescriber should not exceed regardless of how a condition is responding. This calculator multiplies weight by those two figures and halves the daily total for the twice-daily schedule — it does not decide whether naproxen is the right drug for a given child, which is a judgment only a physician who has examined that child can make.
Naproxen suspension's pediatric use is established for children roughly 2 years and older with a diagnosed rheumatic condition such as juvenile idiopathic arthritis, under ongoing physician supervision that typically includes monitoring for the stomach and kidney effects any NSAID can cause with regular use. It was never studied or labeled as a general home fever-and-pain reducer for children the way acetaminophen or ibuprofen are, which is exactly why the OTC Aleve label declines to offer a self-care figure for this age group at all.
- Enter the child's weight in kilograms — divide pounds by 2.2 first if that's what you have.
- Read the total daily dose in mg, then the per-dose figure for a twice-daily schedule.
- Check the absolute maximum in mg — a prescriber should not exceed this regardless of adjustments.
- Use these figures only alongside a specific prescription and dosing instructions from a physician.
Worked example — 20 kg child, prescribed by a physician
A 20 kg child prescribed naproxen: total daily dose is 10 × 20 = 200 mg, split into two doses of 200 ÷ 2 = 100 mg roughly twelve hours apart. The absolute daily ceiling for this weight is 15 × 20 = 300 mg — a prescriber's total should not cross that line even if a dose is adjusted mid-treatment.
A 30 kg child scales the same arithmetic: 10 × 30 = 300 mg total, 150 mg per dose, and a 15 × 30 = 450 mg ceiling. At 40 kg it becomes 10 × 40 = 400 mg total, 200 mg per dose, with a 15 × 40 = 600 mg maximum — every figure a pharmacist or prescriber can check against what's written on the bottle, not a number a caregiver should choose alone.
Questions
Can I give my child Aleve using this calculator without seeing a doctor first?
No. The OTC Aleve label has no self-care dose for a child under 12 at all — it says to ask a doctor. This calculator works out the FDA-approved prescription figures for naproxen suspension, meant to be used only after a physician has diagnosed a condition and written a specific prescription, not as a home fever-and-pain reducer a caregiver reaches for on their own.
What is this dose actually prescribed for?
Most commonly juvenile idiopathic arthritis and similar diagnosed rheumatic conditions in children, where a physician has decided naproxen is appropriate and needs to titrate the dose to the child's current weight. It is not prescribed as a substitute for acetaminophen or ibuprofen for an ordinary childhood fever.
Why doesn't the OTC Aleve label have any dose for children under 12?
Because naproxen's pediatric safety and dosing were only formally established through the prescription suspension formulation under physician supervision, not for unsupervised over-the-counter use in that age group. The label's own directions reflect that gap directly by saying to ask a doctor rather than printing a self-care number.
How does the twice-daily dose relate to the total daily dose?
The total daily dose is simply divided by two for a morning-and-evening schedule roughly twelve hours apart — a 20 kg child's 200 mg total becomes two 100 mg doses, for example. A prescriber may adjust the split or the timing for a specific child, so always follow the schedule written on the prescription rather than assuming an even twelve-hour split applies.
What should I do if I think my child got too much naproxen?
Call Poison Control at 1-800-222-1222 (US) immediately, or call emergency services if your child is having trouble breathing, is unresponsive, or you suspect a serious overdose. Do not wait for symptoms to appear before calling — have the bottle or prescription label on hand so you can report the exact strength and amount involved.
Is naproxen safe for a very young child?
Naproxen suspension's pediatric labeling starts at roughly 2 years old, and only for specific diagnosed conditions under a physician's ongoing supervision, not as general self-care. Below that age, or outside a specific prescription, naproxen dosing should not be attempted at all without direct medical guidance.
References
- FDA — NAPROSYN (naproxen) Oral Suspension, Prescribing Information (accessdata.fda.gov, NDA 018965)
- DailyMed — Aleve (naproxen sodium), OTC Drug Facts Label
Read this first: This instrument computes a screening figure from population formulas — it is not a diagnosis, and it cannot see the whole picture a clinician can. Use it to inform a conversation, not to replace one.