From the Research
The recommended dose of Tylenol (acetaminophen) for a 9-month-old infant is 15 mg per kilogram of body weight every 4-6 hours as needed, not exceeding 5 doses in 24 hours, as supported by the most recent and highest quality study 1. For most 9-month-olds who typically weigh between 7-10 kg (15-22 pounds), this translates to approximately 105-150 mg per dose.
- Tylenol for infants comes as a liquid suspension, usually in a concentration of 160 mg per 5 mL.
- You should always use the measuring device provided with the medication for accurate dosing.
- Before giving any medication, check your child's weight and verify the correct dose, as giving too much acetaminophen can cause liver damage.
- It's essential to record when doses are given to avoid accidental overdosing.
- If your infant has a fever that persists beyond 3 days, or if symptoms worsen, contact your pediatrician.
- Never give adult formulations of acetaminophen to infants, as these are too concentrated and can lead to dangerous overdosing. The study 1 used a mathematical model of acetaminophen absorption to predict plasma concentrations and compared them with the range required to reach and achieve antipyresis, providing a strong basis for the recommended dose.
- The dose of 15 mg/kg is supported by the study as it is adequate to reach the plasma concentration value for antipyresis.
- The study also highlights the importance of weight-based dosing, which is consistent with the recommended dose.
- In contrast, older studies such as 2 and 3 provide less specific guidance on dosing, while study 4 emphasizes the importance of accurate dosing but does not provide a specific recommendation.
- Study 5 is not relevant to the question as it discusses midazolam, not acetaminophen.