How to Safely Give Medicine to Your Child — Weight-Based Dosing Guide
It is 2 in the morning. Your child is crying with a temperature of 39 degrees. You reach for the paracetamol syrup and stare at the leaflet. “Children aged 7 to 12: 5-10 ml.” But your child is 4 years old. Or maybe she is 8 but weighs as much as a 12-year-old. How much should you give? How much is too much? And why is the dosing listed by age in the first place, when children of the same age can weigh twice as much as each other?
These are questions parents face every day. And the answers are not as simple as the leaflet suggests.
Why children’s dosing is different from adults’
A child is not a small adult. Their body processes medicines differently:
- Liver — in newborns and infants the liver enzymes are immature. Medicines are metabolised more slowly, which means they stay in the body longer and can reach higher concentrations.
- Kidneys — in young children renal filtration is lower. Medicines cleared by the kidneys persist for longer.
- Body composition — newborns have proportionally more water and less fat tissue than adults. This affects how a medicine is distributed throughout the body.
- Body surface area — the ratio of skin surface area to body mass is much greater in children than in adults. This influences how medicines are absorbed through the skin.
For these reasons, paediatric dosing is not a simple calculation of “half the adult dose.” Every medicine has its own paediatric guidelines, based on clinical studies conducted with children.
How to calculate the correct dose
There are two main approaches to dosing medicines for children:
Weight-based dosing (mg/kg)
This is the most common and most accurate method. The dose is expressed as a number of milligrams of medicine per kilogram of the child’s body weight.
Example — paracetamol:
- Recommended dose: 10-15 mg/kg/dose
- Child weighs 20 kg: 20 x 15 = 300 mg per dose
- Syrup at 120 mg/5 ml: 300 / 120 x 5 = 12.5 ml
Example — ibuprofen:
- Recommended dose: 5-10 mg/kg/dose
- Child weighs 15 kg: 15 x 10 = 150 mg per dose
- Syrup at 100 mg/5 ml: 150 / 100 x 5 = 7.5 ml
These calculations may look daunting at 2 a.m., but once you have done them once for your child’s current weight you can note the result and reuse it until their weight changes significantly. A kitchen scale and a dosing syringe are more important than any phone-calculator trick.
Age-based dosing
Leaflets often list doses by age bracket. This is convenient, but far less precise — because children of the same age can have very different body weights. A 5-year-old may weigh 15 kg or 25 kg. A dose labelled “for children aged 4-6” will be too low for one child and too high for another.
Rule of thumb: if you know your child’s weight, dose by mg/kg. If you do not have their weight to hand, use the age brackets on the leaflet as a rough guide — but err on the side of caution.
The most common mistakes parents make
Mistake 1: Confusing preparation concentrations
Paediatric syrups come in different concentrations. Paracetamol may be available as 120 mg/5 ml or 250 mg/5 ml. If you calculate the dose for one concentration and then measure out the other, you could give twice as much — or half as much — as intended.
Always check the concentration printed on the bottle before measuring a dose. If you have switched brands or bought a different product, re-do the calculation from scratch.
Mistake 2: Using a kitchen spoon
A kitchen spoon is not a measuring instrument. Its capacity ranges from roughly 2.5 ml to 7 ml, while “one teaspoon” on a leaflet means exactly 5 ml. Use the dosing syringe or measuring cup supplied with the medicine. This is not pedantry — it is the difference between a therapeutic dose and one that either does nothing or causes harm.
Mistake 3: Dosing “generously” because the child is big for their age
“I give him a bit more because he is tall for his age” — this is dangerous reasoning. Paediatric dosing already includes a safety margin. Exceeding the recommended dose does not produce a better therapeutic effect; it only increases the risk of side effects. If the calculated dose falls within the recommended range, it is enough.
Mistake 4: Combining preparations that contain the same active ingredient
This is the same trap that catches adults, but it is more dangerous in children because the margin for error is smaller. A fever syrup (containing paracetamol) plus a cold-and-flu syrup (which also contains paracetamol) equals a double dose of paracetamol. Always read the full list of active ingredients on every product you give your child. If two medicines share an ingredient, you must account for both when calculating the total dose.
Mistake 5: Giving children adult medicines
Adult tablets and capsules are not designed for children. You cannot split them into quarters and assume you have an appropriate dose. The active ingredient may not be evenly distributed across the tablet, some formulations are designed to release slowly and must not be broken, and the excipients may not be suitable for young children. Dedicated paediatric forms — syrups, suspensions, suppositories, drops — exist precisely because they allow accurate dosing and safe administration.
When you should NEVER give medicine without consulting a doctor
There are situations where giving your child medicine on your own carries serious risk:
- Newborns and infants under 3 months — a fever in a baby this young always warrants immediate medical attention. Do not attempt to manage it at home with over-the-counter medicine.
- Vomiting — if the child cannot keep oral medicine down, they need an alternative route of administration (suppositories, or in severe cases intravenous delivery in hospital).
- Symptoms lasting longer than 3 days — fever, pain, or cough that does not improve despite treatment needs professional evaluation, not an increased dose.
- An unfamiliar medicine — do not give your child a medicine you do not recognise, even if someone recommends it. Check the leaflet, check the active ingredient, check the age suitability.
- Antibiotics — never without a prescription. Antibiotic dosing in children is strictly defined and requires a medical diagnosis. Incorrect antibiotic use contributes to resistance and can cause harm.
How mojApteczka helps parents
The paediatric classification feature in mojApteczka labels every medicine in your home cabinet as one of:
- Child-safe — safe and intended for children.
- Adult standard — for adults, not for children.
- Adult strong — prescription-strength, definitely not for children.
- Veterinary — not for human use.
This means that at 2 a.m., when your child has a fever, you can open the app and immediately see which medicines in your cabinet are appropriate. You do not have to read every leaflet in the dark or second-guess yourself under pressure.
You can also check medicine interactions — because if your child is already taking an antibiotic and you want to give ibuprofen for a fever, it is worth knowing whether that combination is safe before you administer it.
If you are looking for more guidance on managing medicines safely in a household with children, visit mojApteczka for parents.
A few practical habits that make a real difference
Beyond the dosing calculations, a handful of everyday practices can significantly reduce the risk of medicine errors with children:
- Weigh your child regularly. Keep a recent weight noted somewhere accessible — on your phone, on the fridge, wherever you will find it at 2 a.m. Children’s weight changes quickly, and a dose calculated six months ago may no longer be correct.
- Store only one concentration of each medicine. If you have both the 120 mg/5 ml and the 250 mg/5 ml paracetamol syrup in the cabinet, the chance of grabbing the wrong one in the dark goes up dramatically.
- Write the dose on the box. Once you have calculated the correct dose for your child, write it directly on the medicine box with a marker. Include the child’s weight at the time of calculation. When the weight changes, recalculate and update the note.
- Keep a dosing log. When a child is ill and receiving multiple doses throughout the day, it is easy to lose track — especially if more than one parent or carer is involved. A simple note of “what, how much, when” prevents accidental double-dosing.
- Do not mix medicines in food without checking. Some medicines interact with dairy, some lose effectiveness when mixed with juice, and some must be taken on an empty stomach. The leaflet will tell you, but only if you read it.
Medical disclaimer: This article is for informational and educational purposes only. It does not constitute medical advice and does not replace consultation with a doctor or pharmacist. Medicine dosing for children should always be discussed with a paediatrician or pharmacist. If in doubt, contact your doctor. In a life-threatening emergency, call your local emergency number (112 in Europe, 911 in the US).
Have questions or suggestions? Write to us: kontakt@mojapteczka.pl