Child Health8 min read

Paracetamol vs Ibuprofen for Children: Pediatrician's Guide

Dra. Paula Andrade

CRM-SP 204778 | RQE 131771 | Título SBP 2024

Licensed in Brazil — Itaim Bibi, São Paulo

Reviewed by Pediatrician

Your child has a fever and there are two bottles in the medicine cabinet — paracetamol (acetaminophen) and ibuprofen. Which one do you reach for? This is one of the most common questions I receive from parents, and the answer is not always obvious. In this guide I will walk you through exactly when to use each medication, how to calculate doses by weight, and the mistakes that can lead to serious complications.

Quick Summary

Paracetamol: from birth, every 4–6 h, 10–15 mg/kg

Ibuprofen: from 6 months only, every 6–8 h, 5–10 mg/kg

Never give ibuprofen during chickenpox — serious risk of skin infection

Do not alternate the two medications — no proven benefit, higher risk of dosing errors

Always dose by current weight, not by age

Paracetamol vs Ibuprofen: Side-by-Side Comparison

Before diving into doses, here is a clear comparison of the two medications so you can choose the right one for each situation:

FeatureParacetamolIbuprofen
Minimum ageAny age (from birth)6 months
MechanismAnalgesic + antipyreticNSAID: anti-inflammatory + analgesic + antipyretic
Dosing intervalEvery 4–6 hoursEvery 6–8 hours
Max daily doses5 doses / 24 h4 doses / 24 h
Anti-inflammatory?NoYes
Best for ear infections?Second choiceFirst choice
Safe in chickenpox?YesNo — contraindicated
Safe with asthma?YesUse with caution

Paracetamol Dose by Weight

The standard dose is 10 to 15 mg per kg, every 4 to 6 hours, with a maximum of 5 doses in 24 hours. Do not exceed 75 mg/kg/day.

Child weightMinimum dose (10 mg/kg)Maximum dose (15 mg/kg)
5 kg50 mg75 mg
8 kg80 mg120 mg
10 kg100 mg150 mg
12 kg120 mg180 mg
15 kg150 mg225 mg
20 kg200 mg300 mg

Tip:In Brazil, paracetamol syrup is typically sold as 200 mg/mL (infant drops) or 32 mg/mL (children's syrup). Check the label concentration before measuring — the volume you give depends on the product's concentration.

Ibuprofen Dose by Weight

The dose is 5 to 10 mg per kg, every 6 to 8 hours, maximum 4 doses in 24 hours. Use 5 mg/kg for fever below 39°C and 10 mg/kg for fever at or above 39°C.

Child weightLow fever (5 mg/kg)High fever ≥39°C (10 mg/kg)
7 kg35 mg70 mg
8 kg40 mg80 mg
10 kg50 mg100 mg
12 kg60 mg120 mg
15 kg75 mg150 mg
25 kg125 mg250 mg

When to Use Each Medication

Choose Paracetamol when…

  • Baby is under 6 months old
  • Child has chickenpox (varicella)
  • Child has asthma or aspirin sensitivity
  • Simple fever with no inflammatory signs
  • After vaccination — first-line choice
  • You are unsure which to use

Prefer Ibuprofen when…

  • Child is over 6 months old
  • Ear infection (otitis media) — anti-inflammatory helps
  • Throat pain with visible swelling
  • Musculoskeletal pain or injury
  • Dental pain
  • High fever ≥39°C needing longer effect (6–8 h)

5 Dangerous Mistakes Parents Make

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Mistake 1: Dosing by age instead of weight

Package inserts list doses by age as a convenience, but children of the same age can differ greatly in weight. A 12-month-old might weigh 8 kg or 11 kg — that is nearly a 40% difference in the correct dose. Always calculate by current weight.

Mistake 2: Alternating paracetamol and ibuprofen

There is no solid evidence that alternating provides better fever control than a single medication used correctly. Alternating increases the risk of confusion about timing, double-dosing, and kidney/liver stress. If one medication is not working, call your pediatrician.

Mistake 3: Giving ibuprofen during chickenpox

This is a serious contraindication. Ibuprofen during chickenpox significantly increases the risk of invasive group A streptococcal infections and necrotizing fasciitis (flesh-eating bacteria). Always use paracetamol for chickenpox.

Mistake 4: Not waiting long enough for the medication to work

Fever typically takes 30 to 60 minutes to start dropping after an antipyretic. Parents often assume the medication failed and give a second dose too early, leading to overdose. Time the doses from when the medication was given, not when the fever was measured.

Mistake 5: Confusing different concentrations of the same drug

In Brazil, paracetamol drops (200 mg/mL) and children's syrup (32 mg/mL) are very different concentrations. Giving infant drops by the spoon — instead of drops — can cause a 6x overdose. Always read the label and measure carefully.

When to Go to the Emergency Room

Give the antipyretic — but also seek emergency care immediately if any of these signs appear:

  • Baby under 3 months with any fever (38°C or above)
  • Fever not responding 1 hour after correct dose
  • Skin rash — especially purple/red spots that do not fade under pressure
  • Difficulty breathing or unusual breathing sounds
  • Child is extremely drowsy, limp, or cannot be consoled
  • Fever lasting more than 3 consecutive days
  • Complete refusal to drink fluids
  • Signs of dehydration: sunken eyes, dry mouth, no tears, no wet diapers for 8+ hours

Important: Chickenpox (Varicella)

If your child has chickenpox, never give ibuprofen or any NSAID. The risk of invasive bacterial skin infections (including necrotizing fasciitis) is well-documented. Use paracetamol only, and consult your pediatrician for antihistamines to manage itching.

Storage and Safety Tips

  • Store all medications at room temperature, away from humidity and sunlight
  • Check expiration dates regularly — discard expired bottles
  • Keep medications out of reach of children — accidental ingestion is a leading cause of childhood poisoning
  • Use only the measuring device included in the package — kitchen spoons are inaccurate
  • Record the time of each dose to avoid accidental double-dosing

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Frequently Asked Questions

Paracetamol or ibuprofen: which is better for fever in children?
Both are effective for fever. Paracetamol (acetaminophen) is the first choice for any age — it can be used from birth. Ibuprofen is indicated from 6 months of age and has an additional anti-inflammatory effect, making it preferred for pain with an inflammatory component, such as ear infections. The choice depends on age, type of pain, and individual contraindications.
What is the correct paracetamol dose for children by weight?
The dose of paracetamol is 10 to 15 mg per kg of body weight, every 4 to 6 hours, with a maximum of 5 doses in 24 hours. Example: a 12 kg child can receive 120 mg to 180 mg per dose. Always calculate by current weight — never by age.
What is the correct ibuprofen dose for children by weight?
The dose of ibuprofen is 5 to 10 mg per kg every 6 to 8 hours. For fevers below 39°C use 5 mg/kg; above 39°C use 10 mg/kg. Example: a 12 kg child can receive 60 mg to 120 mg per dose. Ibuprofen can only be used from 6 months of age.
Can I alternate paracetamol and ibuprofen for fever?
It is not recommended. There is no solid scientific evidence that alternating is more effective than a single medication used correctly. In addition, alternating increases the risk of dosing errors and places extra burden on the kidneys and liver. If the medication is not controlling the fever, consult your pediatrician.
Can ibuprofen be used in children with chickenpox?
No. Ibuprofen is contraindicated in chickenpox because it increases the risk of serious bacterial skin infections. In these cases, use paracetamol only. The use of anti-inflammatory drugs (NSAIDs) during chickenpox is associated with serious complications, such as necrotizing infections.
When should I call the pediatrician even after giving fever medicine?
Seek the pediatrician if: fever does not subside within 1 hour of antipyretic; the child is very lethargic or inconsolable; fever lasts more than 3 days; skin rashes, breathing difficulty, or complete refusal of fluids appear; or if the baby is under 3 months old with any fever.

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Every child is unique. Dr. Paula provides safe, personalized medication guidance during in-person consultations.

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Consultório no Itaim Bibi, São Paulo | CRM-SP 204778 | RQE 131771

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