In the United States, ibuprofen is approved for over-the-counter use in infants 6 months and older. Below that age, it should only be given if a doctor specifically prescribes it. This 6-month threshold exists because younger infants face higher risks of kidney problems and gastrointestinal side effects, and the FDA has not approved OTC labeling for that age group.
Why 6 Months Is the Cutoff
The primary concerns with giving ibuprofen to very young infants are kidney stress, gastrointestinal bleeding, and a small risk of other serious complications. Infant kidneys are still maturing in the first several months of life, and ibuprofen reduces blood flow to the kidneys in a way that fully developed organs handle easily but immature ones may not.
A pharmaceutical company actually petitioned the FDA in 1999 to allow OTC labeling for infants under 6 months, but the application was rejected because the safety data included too few babies in that age group (only 319). Many doctors in the U.S. interpret the lack of OTC labeling as a signal that ibuprofen is unsafe before 6 months, though the reality is more nuanced: there simply isn’t enough data to confirm it’s safe for widespread unsupervised use. In the UK, the NHS allows ibuprofen for babies as young as 3 months old (weighing at least 5 kg, or about 11 pounds), and babies 1 to 3 months old can receive it with a doctor’s prescription.
Weight Matters More Than Age
Once your child is old enough, dosing is based on weight, not age. The standard pediatric dose is 4 to 10 mg per kilogram of body weight per dose, given every 6 to 8 hours as needed. No single dose should exceed 400 mg, and the total daily amount should stay under 40 mg per kilogram or 1,200 mg, whichever is lower.
Always use the measuring device that comes with the product. Kitchen spoons vary too much to be reliable. Children’s liquid ibuprofen typically comes in a single concentration now, but it’s still worth checking the label every time you buy a new bottle, since formulations can vary between brands.
Ibuprofen vs. Acetaminophen for Young Children
For children under 6 months, acetaminophen (Tylenol) is the only OTC pain and fever reliever recommended, and even that should be avoided in babies younger than 3 months without a doctor’s guidance. Once your child reaches 6 months, both options are available, and the evidence slightly favors ibuprofen for fever and pain.
A meta-analysis reviewed by the American Academy of Family Physicians found that children who received ibuprofen had temperatures about 0.38°C lower within four hours compared to those given acetaminophen. They were also nearly twice as likely to be fever-free at the four-hour mark. For pain, ibuprofen performed better too: children were 25% more likely to be pain-free within 4 to 24 hours. The overall conclusion was that ibuprofen’s benefits outweigh its harms compared to acetaminophen in children under two, as long as it’s used appropriately.
That said, acetaminophen is gentler on the stomach and kidneys, which makes it the better choice if your child is dehydrated, vomiting, or has a sensitive stomach.
How to Give It Safely
Ibuprofen can be given with food or milk to reduce the chance of stomach upset, though it isn’t strictly required. Space doses at least 6 hours apart, and don’t exceed three doses in 24 hours unless your pediatrician directs otherwise.
A few situations call for extra caution or avoiding ibuprofen entirely:
- Dehydration: If your child has been vomiting, has diarrhea, or isn’t drinking enough fluids, ibuprofen puts additional strain on the kidneys. Use acetaminophen instead until they’re well hydrated.
- Asthma: Some children with asthma are sensitive to ibuprofen, which can trigger wheezing or worsen symptoms. If your child has asthma and hasn’t taken ibuprofen before, check with your pediatrician first.
- Chickenpox: Ibuprofen has been linked to skin complications during chickenpox infections and is generally avoided during active illness.
- Empty stomach in older kids: While not dangerous as a one-time event, repeated doses on an empty stomach increase the risk of stomach irritation over time.
Quick Age Reference
- Under 3 months: No OTC pain relievers without a doctor’s direction.
- 3 to 5 months: Acetaminophen is the standard choice. Ibuprofen only if a doctor prescribes it (more common in the UK than the U.S.).
- 6 months and older: Both ibuprofen and acetaminophen are safe OTC options. Dose ibuprofen by weight, every 6 to 8 hours as needed.