What is the recommended dose of Tylenol (acetaminophen) for a 9-month-old child weighing 20 pounds?

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From the Guidelines

For a 9-month-old child weighing 20 pounds, the recommended dose of Tylenol (acetaminophen) is 90 mg every 4-6 hours as needed, not to exceed 5 doses in 24 hours. This dosage is based on the standard pediatric dosing of 10-15 mg per kg of body weight, with the child's weight being approximately 9 kg. When giving liquid acetaminophen to an infant, use the concentration specifically formulated for infants (160 mg/5 mL), and measure precisely with the dosing syringe or cup provided with the medication, as noted in general pediatric guidelines 1. Never use a kitchen spoon for measurement. Always check the product label to confirm the concentration before administering. It's essential to treat fever or pain promptly in infants, but avoid giving acetaminophen for more than 3 consecutive days without consulting a healthcare provider. Some studies suggest administering acetaminophen, 15 mg/kg of body weight, at the time of vaccination and every 4 hours subsequently for 24 hours 1, but this is more specific to vaccination scenarios. In general practice, for fever or pain management in a 9-month-old child, the dosage of 90 mg every 4-6 hours is appropriate, considering the child's weight and the standard dosing guidelines. If the child's symptoms worsen or don't improve, or if the fever persists beyond 3 days, contact your pediatrician immediately.

From the Research

Recommended Dose of Tylenol for a 9-Month-Old Child

To determine the recommended dose of Tylenol (acetaminophen) for a 9-month-old child weighing 20 pounds, we need to consider the available evidence.

  • The child's weight is 20 pounds, which is approximately 9 kilograms.
  • According to the study 2, the recommended dose of acetaminophen is 10-15 mg/kg at 4-hour intervals.
  • Based on this recommendation, the dose for a 9-kilogram child would be 90-135 mg of acetaminophen per dose.
  • Another study 3 suggests that weight-based dosing is more accurate than age-based dosing, and the recommended dose range of 10-15 mg/kg is supported.
  • The study 4 also recommends a dose of 20 mg/kg as a single oral dose for antipyretic effect, but this is higher than the generally recommended range.
  • The study 5 suggests that 10 mg/kg is considered safe and effective for antipyresis in children.
  • The study 6 emphasizes the importance of using weight-based dosing to avoid inaccurate dosing, which is a common problem among parents.

Calculation of Recommended Dose

Based on the recommended dose range of 10-15 mg/kg, we can calculate the dose for a 9-kilogram child as follows:

  • 10 mg/kg x 9 kg = 90 mg per dose
  • 15 mg/kg x 9 kg = 135 mg per dose Therefore, the recommended dose of Tylenol for a 9-month-old child weighing 20 pounds would be 90-135 mg per dose, every 4 hours as needed 2, 3, 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Pediatric dosing of acetaminophen.

Pediatric pharmacology (New York, N.Y.), 1983

Research

[Optimal dose of acetaminophen in children].

Archives francaises de pediatrie, 1990

Research

Acetaminophen and ibuprofen dosing by parents.

Pediatric emergency care, 2000

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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