The paracetamol dose for a baby is calculated based on weight, never age alone. Assurance Maladie recommends 15 mg per kilogram every six hours, or 10 mg per kilogram every four hours, without exceeding 60 mg per kilogram per day. This is the standard guideline and the most common source of errors at home.
What is the exact paracetamol dose for a baby?
The calculation is simple. Multiply the child's actual weight by the single dose, then respect the minimum interval between two doses. A 6-kilogram baby therefore receives 90 mg per dose at 15 mg per kilogram.
Assurance Maladie specifies that the daily total should be divided into four to six doses over 24 hours. The limit of 60 mg per kilogram per day must never be exceeded, even if the fever rises again before the scheduled time.
Why weight rather than age
At the same age, two infants may differ in weight by two kilograms. A dose calculated based on age can therefore result either in an ineffective underdose or an overdose. This is why the oral suspension syringes are graduated in kilograms rather than milliliters.
The weight to use is the current weight, not the weight recorded in the last health record. In an infant who is growing quickly, the difference can widen within a few weeks.
How long can it be given without medical advice?
ANSM sets a clear limit: a maximum of three days in the case of fever and five days in the case of pain, without a consultation. Beyond that, persistent symptoms should be assessed by a doctor.
For very young infants, this guideline must be combined with the age rule. Before three months, any fever requires immediate medical advice, even before considering medication. We explain this approach in detail in our article on fever in infants.
The most common dosing errors
Reported incidents almost never result from a lack of knowledge of the rule. They result from everyday actions carried out while tired or in a hurry.
Using the syringe from another bottle
Each dosing device is calibrated for the concentration of its own bottle. A syringe borrowed from another box or another medication can result in an incorrect dose. The device should be discarded with the bottle it came with.
Combining two medicines containing the same active ingredient
ANSM reminds us that more than 200 medicines marketed in France contain paracetamol, either alone or in combination. A cold syrup and a fever reducer can therefore be combined without anyone realizing it.
The check is simple. Read the ingredients before administering the medicine, and never give two different products without verifying that neither already contains the active ingredient.
Shortening the interval between doses
When the temperature rises again before the scheduled time, the temptation to give the next dose early can be strong. ANSM indicates a minimum interval of four hours between doses. Respecting it is part of the dose, just like the number of milligrams.
Alternating or combining two fever reducers
Assurance Maladie is explicit: use only one type of medicine for fever. Alternating paracetamol and ibuprofen is no more effective and adds the risk of side effects.
Ibuprofen is reserved for children over three months old, when paracetamol is contraindicated, at 20 to 30 mg per kilogram per day. Aspirin should not be given to a child without medical advice because of the risk of Reye's syndrome.
What are the risks of an overdose?
The main risk is liver damage. ANSM reminds us that paracetamol overdose is the leading cause of drug-induced liver transplantation in France. The damage can be irreversible.
The difficulty lies in the lack of immediate warning signs. An overdosed child may not necessarily show symptoms during the first few hours. If there is any doubt about a dose that was given, call a poison control center or 15 without waiting for symptoms to appear.
The role of the pharmacist
Dispensing the medicine is an opportunity to have the calculation checked. The pharmacist verifies the bottle's concentration, the device's graduations, and the absence of duplication with another treatment currently being used. This is free and takes two minutes.
What paracetamol does not do
It does not treat the cause of the fever. It lowers the temperature and relieves discomfort while the body does its work. A fever that responds to the medicine therefore says nothing about how serious it is.
It also does not replace a reliable temperature measurement. A thermometer suited to the child's age helps avoid false alarms and unnecessary doses, as we explain in our guide to choosing a baby thermometer. For bath time, we compared the practical value of floating models in our article about bath thermometers.
Finally, it is not a treatment for teething. Products sold to soothe teething have not been proven effective, and some present risks documented by health authorities, as our article on amber teething necklaces explains.
When the fever has an identifiable cause
Medication provides relief, but it does not eliminate the need to look for the cause. An infant ear infection often involves fever and crying when lying down. A moderate fever within 48 hours after an injection is an expected reaction, as discussed in our article on the vaccination schedule.
Key points to remember
- The dose is calculated based on actual weight: 15 mg per kilogram every six hours, or 10 mg per kilogram every four hours.
- The maximum is 60 mg per kilogram per day, divided into four to six doses.
- A maximum of three days for fever and five days for pain without medical advice.
- A syringe should only be used with the bottle it came with.
- Use only one fever reducer at a time, and always check the ingredients of other medicines.
If there is any doubt about a dose, the primary care doctor, pharmacist, or 15 can provide an immediate answer. Other questions about caring for very young children are addressed on our frequently asked questions page.
Sources
- Assurance Maladie (ameli.fr), “Medicines for fever in children,” updated September 3, 2024.
- ANSM, thematic file “Paracetamol,” published February 8, 2024, and updated June 25, 2024.
- ANSM, “Do you know how to use paracetamol properly for pain and fever?” October 18, 2021.
