Fever Not Coming Down With Paracetamol: What to Do
A fever that does not fully drop after paracetamol is common and not usually dangerous. The goal is comfort, not a normal temperature. Check the dose is right for your child's weight and that enough time has passed, then watch how your child looks rather than the number.
What paracetamol actually does
Paracetamol lowers a fever by around 1°C to 1.5°C. It does not switch the fever off or return the temperature to normal, and it is not meant to. A reading that falls from 39.5°C to 38.2°C is the medicine working as designed, even though 38.2°C is still a fever.
The infection driving the fever is still there until the body clears it, so the temperature will often climb again as each dose wears off. This back-and-forth over a couple of days is the normal pattern, not a sign the medicine has failed.
Five things to check first
If the fever genuinely is not moving at all, run through these before anything else. The most common reason a fever does not respond is a dose that is too small or given too soon.
Paracetamol is dosed by weight, not age. A common reason for a weak effect is a dose set for a younger, lighter child. Check it against your child's current weight.
Paracetamol takes 30 to 60 minutes to start working. Checking at 15 minutes is too early. Recheck nearer the 1 hour mark.
Syrups come in different concentrations. Measuring the right volume of the wrong strength gives the wrong dose. Confirm the mg per 5 ml on the label.
If the dose was spat out or vomited soon after, your child may have had little of it. Note the time and watch before re-dosing.
A child who has perked up and is drinking after a dose is responding, even if the number is still up. Behaviour tells you more than the thermometer.
→ Check the correct paracetamol dose by weight
→ Worried you gave too much? Overdose signs and what to do
Comfort is the goal, not a normal number
The point of fever medicine is to help your child feel better, not to get the thermometer to read normal. A fever is part of how the body fights infection. If your child is more comfortable, drinking, and resting after a dose, the medicine has done its job even if a fever remains.
Chasing a normal reading by giving more medicine than the safe dose, or giving it too often, is where harm comes from. Stay within the dose and interval for your child's weight and judge progress by how they look, not by the number alone.
Adding or alternating ibuprofen
If your child is over 3 months, uncomfortable, and there is no reason to avoid it, ibuprofen can be used instead of paracetamol or alternated with it during a persistent high fever. Alternating can help bridge the gap when one medicine wears off before the next dose of the same one is due.
Track each medicine separately, because the intervals differ: paracetamol every 4 to 6 hours, ibuprofen every 6 to 8 hours. Do not give both at the same moment as a default, and do not use ibuprofen if your child is dehydrated, has chickenpox, or is already taking another NSAID such as diclofenac.
→ How to alternate paracetamol and ibuprofen safely
When to seek help
Call your GP or polyclinic the same day if:
- The fever has lasted more than 3 days without a clear cause.
- Your child seems unwell or unusually quiet even between doses of medicine.
- They are drinking much less than normal, or passing urine much less often.
- You have checked the dose and timing and the fever still does not respond at all over a day.
Go to your nearest 24-hour Children's Emergency immediately if your child has a fever and any of these:
A rash of red or purple spots that does not fade when you press a glass against it
Difficulty breathing: chest skin pulling in, nostrils flaring, or grunting
Very drowsy, floppy, or hard to wake
A seizure: call 995 (Singapore's emergency number) if it lasts longer than 5 minutes or your child will not wake afterwards; otherwise go to A&E for assessment
A stiff neck, or pain looking at bright light
No urine passed in 12 hours and refusing all fluids
Under 3 months old with any fever of 38.0°C or above
→ Toddler fever 39°C: when to monitor vs seek help
→ Fever at night: when should parents worry?
→ How long does a fever last in a child?
Frequently asked questions
Why is my child's fever not coming down with paracetamol?+
Paracetamol lowers a fever by about 1°C to 1.5°C, it does not return the temperature to normal. A drop from 39.5°C to 38.2°C means it is working, even though it is still a fever. If there is no change at all, the most common reasons are an underdose for your child's weight, not enough time passed yet, or a strong infection driving the temperature back up.
How much should paracetamol lower a fever?+
Expect a fall of roughly 1°C to 1.5°C within about an hour, lasting a few hours before the next dose is due. A partial drop and a child who becomes more comfortable is the goal. Paracetamol is not designed to make the temperature normal, so a remaining low-grade fever is expected and not a failure.
How long does paracetamol take to work on a fever?+
It usually begins to act within 30 to 60 minutes, with the fullest effect around the 1 to 2 hour mark. If you check 15 minutes after a dose and see no change, that is too early. Recheck nearer the 1 hour mark before deciding it has not worked.
Can I give ibuprofen if paracetamol is not bringing the fever down?+
If your child is over 3 months and uncomfortable, ibuprofen can be used as an alternative or alternated with paracetamol, provided there is no reason to avoid it. Track each medicine separately because their dose intervals differ. Do not double up by giving both at the exact same time as a default.
Is a fever that will not come down dangerous?+
A high number on its own is rarely the danger. How your child looks and behaves matters more. A fever that stays up but a child who is drinking, responsive, and settling is reassuring. A fever combined with drowsiness, breathing difficulty, a non-blanching rash, or a child who cannot be roused needs urgent assessment regardless of the number.
When should I see a doctor about a fever that won't go down?+
See your GP or polyclinic the same day if the fever has lasted more than 3 days, your child seems unwell even between doses, or they are drinking much less than usual. Go to the nearest 24-hour Children's Emergency for any red-flag sign, and treat any fever of 38.0°C or above in a baby under 3 months as urgent.