Babies can have ibuprofen starting at 6 months of age. This is the threshold recommended by the FDA and most pediatric guidelines in the United States, based on concerns about kidney function and stomach irritation in younger infants. Before 6 months, acetaminophen is the standard option for fever and pain relief.
Why 6 Months Is the Cutoff
The main reasons ibuprofen is restricted before 6 months relate to how a young infant’s body processes the drug. Ibuprofen can stress the kidneys, and younger babies have less mature kidney function. There are also concerns about stomach and intestinal irritation, and a small theoretical risk of Reye’s syndrome. A study published in PLOS One that looked back at infants who received ibuprofen before 6 months did not find significantly more kidney or stomach problems compared to older infants, but the FDA has not changed its guidance. Safety and efficacy in babies under 6 months simply haven’t been formally established through the kind of studies regulators require.
If your baby is younger than 6 months and has a fever or is in pain, acetaminophen (Tylenol) is the go-to. It can be given from 2 months of age onward for most infants.
How Dosing Works
Ibuprofen for infants is dosed by weight, not age. Your child’s weight in pounds determines how much to give, regardless of whether they’re 7 months or 14 months old. The standard interval is every 6 to 8 hours as needed, up to 3 or 4 times in a 24-hour period. If you’re giving it 4 times a day, leave at least 4 hours between doses. If 3 times, leave at least 6 hours.
Here’s a simplified guide based on weight:
- 12 to 17 pounds: 2.5 mL of children’s liquid (100 mg/5 mL)
- 18 to 23 pounds: 3.75 mL of children’s liquid
- 24 to 35 pounds: 5 mL (one teaspoon) of children’s liquid
- 36 to 47 pounds: 7.5 mL of children’s liquid
Always use the measuring syringe or cup that comes with the product. More than 50% of parents have been shown to give an incorrect dose of common pain relievers, so precision matters. Check the concentration on the bottle every time.
Infant Drops vs. Children’s Liquid
This is one of the most important things to get right. Infant ibuprofen drops are more concentrated (200 mg per 5 mL) than children’s liquid (100 mg per 5 mL). That means the infant version has twice the medication in the same volume. Swapping one for the other without adjusting the amount could mean your child gets double the intended dose, or half of it.
A study in Pediatric Research found significantly more dosing errors with the infant concentration compared to the children’s version. The average error was 39 mg off the target dose with infant drops versus 27 mg with the children’s liquid. Read the label carefully each time, even if you’ve given the same product before.
When to Avoid Ibuprofen
Even after 6 months, there are situations where ibuprofen is the wrong choice. The most important one is dehydration. If your baby has a stomach bug with vomiting or diarrhea and isn’t keeping fluids down well, ibuprofen can significantly increase the risk of kidney injury. One study of dehydrated children with gastroenteritis found that ibuprofen exposure more than doubled the risk of acute kidney injury, independent of how dehydrated the child was. In that group, 54% of children who received ibuprofen developed some degree of kidney stress.
The takeaway is straightforward: if your child is sick with something that causes fluid loss, stick with acetaminophen instead. Ibuprofen is also not appropriate for babies with known kidney problems, a history of stomach bleeding, or those who have had an allergic reaction to aspirin or similar pain relievers.
Give It With Food
Ibuprofen can irritate the stomach lining, even in older children and adults. For babies, give it with or just after a feeding, whether that’s breast milk, formula, or solid food. Giving it on an empty stomach increases the chance of nausea, spitting up, or general fussiness from stomach discomfort.
Side Effects to Watch For
The most common side effects in infants are stomach related: nausea, vomiting, diarrhea, or general abdominal discomfort. You might also notice your baby seems a bit bloated or gassy. These are usually mild and resolve on their own.
Less common but more concerning signs include a decrease in wet diapers (which could signal kidney stress), unusual bruising or bleeding, a skin rash, or swelling of the face, hands, or feet. A serious allergic reaction is rare but requires immediate attention. Watch for fast or irregular breathing, wheezing, hive-like swelling on the skin, or puffiness around the eyes. Children who are allergic to aspirin are at higher risk for this type of reaction.
Ibuprofen vs. Acetaminophen
Both work well for fever and mild to moderate pain, but they differ in a few practical ways. Acetaminophen can be used from about 2 months of age, giving it a 4-month head start over ibuprofen. Ibuprofen has anti-inflammatory properties that acetaminophen lacks, which makes it a better choice for pain that involves swelling, like teething or ear infections. Ibuprofen also tends to last a bit longer, with dosing every 6 to 8 hours compared to acetaminophen’s every 4 to 6 hours.
You may have heard about alternating the two medications when a fever won’t break. Both the American Academy of Pediatrics and the UK’s National Institute for Health and Clinical Excellence advise against doing this routinely. The risk of dosing errors goes up when parents are juggling two medications on different schedules, and there’s a theoretical increased risk of liver and kidney stress when both drugs are used together. If a single medication at the right dose and interval isn’t controlling your child’s fever or pain, that’s worth a call to your pediatrician rather than layering on a second drug at home.