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
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:
| Feature | Paracetamol | Ibuprofen |
|---|---|---|
| Minimum age | Any age (from birth) | 6 months |
| Mechanism | Analgesic + antipyretic | NSAID: anti-inflammatory + analgesic + antipyretic |
| Dosing interval | Every 4–6 hours | Every 6–8 hours |
| Max daily doses | 5 doses / 24 h | 4 doses / 24 h |
| Anti-inflammatory? | No | Yes |
| Best for ear infections? | Second choice | First choice |
| Safe in chickenpox? | Yes | No — contraindicated |
| Safe with asthma? | Yes | Use 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 weight | Minimum dose (10 mg/kg) | Maximum dose (15 mg/kg) |
|---|---|---|
| 5 kg | 50 mg | 75 mg |
| 8 kg | 80 mg | 120 mg |
| 10 kg | 100 mg | 150 mg |
| 12 kg | 120 mg | 180 mg |
| 15 kg | 150 mg | 225 mg |
| 20 kg | 200 mg | 300 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 weight | Low fever (5 mg/kg) | High fever ≥39°C (10 mg/kg) |
|---|---|---|
| 7 kg | 35 mg | 70 mg |
| 8 kg | 40 mg | 80 mg |
| 10 kg | 50 mg | 100 mg |
| 12 kg | 60 mg | 120 mg |
| 15 kg | 75 mg | 150 mg |
| 25 kg | 125 mg | 250 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
Not sure which medication your child needs?
Book a consultation and Dr. Paula will evaluate your child and guide you on safe medication use.
Book a ConsultationMistake 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
You May Also Find Helpful
Questions about the right dose for your child?
Every child is unique. Dr. Paula provides safe, personalized medication guidance during in-person consultations.
Consultório no Itaim Bibi, São Paulo | CRM-SP 204778 | RQE 131771
Related Articles
Baby Fever: When to See a Doctor and What to Do at Home
Is your baby's fever an emergency? Temperature chart by age, warning signs, when to go to the ER, and home care tips. Guide by a pediatrician in Sao Paulo.
Baby HealthNormal Baby Temperature by Age: Complete Chart and Measuring Guide
What is a normal baby temperature? Complete chart by age, how to measure correctly, when it's fever, and which thermometer to use. Guide by a pediatrician.