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, often by around 1°C, with the biggest effect at 2 to 3 hours. It starts working in 30 to 60 minutes. 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.
Six 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.
Do not give the same medicine again, even if it came up straight away. Count it as given. Wait about an hour and recheck. If your child is still uncomfortable or 38.5°C or above, ibuprofen may be given on its own schedule, unless one of the ibuprofen cautions below applies. Fever with vomiting
If all of it came straight back out before swallowing, a fresh dose is usually reasonable. If you are not sure how much was swallowed, count it as given.
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.
- Your child is under 3 months, or weighs under 5 kg.
- Dengue is possible. In Singapore, a fever without a clear cause can be dengue in the first few days.
- Your child is vomiting repeatedly, or not drinking well.
- Your child has chickenpox.
- Your child has already had diclofenac (for example a suppository from the clinic) or naproxen. These are the same class of medicine as ibuprofen, so never give them within each other’s dosing window.
- Your child has asthma that has got worse with ibuprofen or aspirin before.
- Your child has kidney problems, a stomach ulcer, or a bleeding disorder.
If you are not sure, ask your pharmacist or GP before giving it.
→ 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.
- A high fever with no clear cause: ask your GP about a dengue test. It is most useful in the first few days.
→ Dengue fever in children: symptoms and warning signs
Call 995 now if your child has a fever and any of these:
- !A seizure lasting more than 5 minutes (give rectal diazepam if a doctor has prescribed it, and still call)
- !Struggling to breathe (skin pulling in under the ribs, nostrils flaring, or grunting), pauses in breathing, or lips turning blue or grey
- !Cannot be woken, or floppy and not responding to you
- !A rash of small red or purple spots that does not fade when you press a glass on it
- !Swelling of the lips, tongue, or face, with any difficulty breathing
- !Cold, clammy, or mottled skin, with drowsiness or restlessness
Go to the nearest 24-hour A&E or children's emergency now if:
- !Pain when looking at bright light
- !A baby under 3 months with a temperature of 38.0°C or above
- !A first febrile seizure, even if it has stopped
- !After a seizure: confused, still drowsy after 30 minutes, or more than one seizure in a day
- !A stiff neck, or crying in pain when bending the head forward
- !Unusually drowsy or hard to wake, but can be woken
- !Dengue warning signs as the fever comes down: tummy pain, repeated vomiting, bleeding gums or nose, or very tired
- !No urine or wet nappy for 12 hours or more
- !No tears when crying, sunken eyes, or a very dry mouth
- !Cannot keep any fluids down
- !Green vomit
- !A temperature above 40°C that is not coming down, and your child seems unwell
→ 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, often by around 1°C, with the biggest effect at 2 to 3 hours. 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 around 1°C, with the biggest effect at 2 to 3 hours, 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 biggest effect at 2 to 3 hours. If you check 15 minutes after a dose and see no change, that is too early. Recheck after about an hour, and remember the effect keeps building until 2 to 3 hours, 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. Use paracetamol, not ibuprofen, if dengue is possible, your child is vomiting or not drinking well, is under 3 months, or has had diclofenac.
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.