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Calculate safe acetaminophen dose for infants (2 months to 2 years)
All Infant Tylenol is now the same concentration as Children's Tylenol
| Age | Weight (lbs) | Weight (kg) | Dose (mg) | mL to Give |
|---|---|---|---|---|
| 0-2 months | Any | Any | Ask Doctor - Do Not Give | |
| 2-3 months | 6-11 | 2.7-5 | 40 | 1.25 |
| 4-11 months | 12-17 | 5.5-7.7 | 80 | 2.5 |
| 12-23 months | 18-23 | 8.2-10.4 | 120 | 3.75 |
| 2 years | 24-35 | 10.9-15.9 | 160 | 5 |
* Always dose by WEIGHT, not age. Weight is more accurate.
No! Since 2011, Infant Tylenol and Children's Tylenol are the SAME concentration (160 mg per 5 mL). The only difference is that Infant Tylenol comes with a dosing syringe designed for smaller amounts. Never use the old concentrated infant drops formula if you still have some—it was 3x stronger.
A rectal temperature of 100.4°F (38°C) or higher is considered a fever in infants. Rectal temperatures are most accurate for babies. For infants under 2 months, ANY fever (100.4°F+) requires immediate medical evaluation.
Motrin (ibuprofen) should NOT be given to infants under 6 months old. For infants 6+ months, alternating may be done under doctor guidance, but it increases the risk of dosing errors. Usually, Tylenol alone is sufficient. Ask your pediatrician first.
Weight is much more accurate because babies of the same age can have very different weights. A 6-month-old could weigh 14 lbs or 22 lbs—they need different doses. Always weigh your baby recently or use their weight from their last doctor visit.
Some studies suggest pre-treating with Tylenol may reduce immune response to vaccines. Most pediatricians now recommend waiting to see if fever develops after vaccination rather than giving Tylenol beforehand. However, this varies—ask your doctor.
If it's just a small dribble, don't re-dose. If most of the dose was spit up immediately (within a few minutes), you can try giving another dose. If you're not sure, wait and see if symptoms improve, or call your doctor. Never give a double dose.
Tylenol typically begins working within 30 minutes to 1 hour. Maximum effect is usually seen at 1-2 hours. The fever-reducing effect lasts 4-6 hours. If fever doesn't improve within 2 hours or keeps coming back, contact your doctor.