What is the appropriate dosing of Diphenhydramine (Benadryl) in pediatric patients?

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Last updated: March 30, 2025View editorial policy

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From the Guidelines

Benadryl (diphenhydramine) dosing in children should be 1 to 2 mg/kg or 25 to 50 mg per dose, administered parenterally, as recommended by the most recent guidelines 1. When considering the use of Benadryl in children, it's essential to weigh the benefits against the potential risks, prioritizing morbidity, mortality, and quality of life. The recommended dose is based on the child's weight, with a maximum dose of 50 mg per dose.

  • For children, the dose can be calculated as 1 to 2 mg/kg per dose, with a maximum dose of 50 mg per dose.
  • It's crucial to use the parenteral route for administration, as recommended by the guidelines.
  • The use of Benadryl should be cautious, and medical supervision is necessary, especially in infants under 2 years, due to potential serious side effects.
  • Benadryl works by blocking histamine receptors to reduce allergy symptoms but can cause drowsiness, dry mouth, and in rare cases, excitability in children.
  • If symptoms persist beyond a few days or worsen, it's essential to consult a healthcare provider immediately. The most recent guidelines from 2010 1 provide the best evidence for the recommended dosing of Benadryl in children, and this should be followed in clinical practice to ensure the best possible outcomes in terms of morbidity, mortality, and quality of life.

From the FDA Drug Label

Directions • take every 4 to 6 hours, or as directed by a physician• do not take more than 6 doses in 24 hours agedose Adults and children over 12 years of age10 mL (25 mg) to 20 mL (50 mg) Children 6 to under 12 years of age10 mL (25 mg) Children under 6 years of ageDo not use

The recommended dosing for diphenhydramine (Benadryl) in kids is as follows:

  • Children over 12 years of age: 10 mL (25 mg) to 20 mL (50 mg), every 4 to 6 hours, not to exceed 6 doses in 24 hours.
  • Children 6 to under 12 years of age: 10 mL (25 mg), every 4 to 6 hours, not to exceed 6 doses in 24 hours.
  • Children under 6 years of age: Do not use 2

From the Research

Benadryl Dosing in Kids

  • There is no direct evidence provided for Benadryl dosing in kids.
  • However, studies suggest that diphenhydramine, the active ingredient in Benadryl, has many side effects, including sedation and risk of toxicity in overdose, particularly in children and older adults 3, 4.
  • Second-generation antihistamines are recommended as alternatives to diphenhydramine due to their similar efficacy and fewer adverse effects 3, 4, 5.
  • Tolerance to the sedative effects of diphenhydramine can develop rapidly, within 3-4 days of administration 6.
  • Newer antihistamines, such as loratadine, desloratadine, cetirizine, and fexofenadine, are considered safer options for the treatment of acute allergic reactions, with less sedation and similar efficacy to diphenhydramine 5.
  • Diphenhydramine can cause drowsiness, performance decrements, and slowing of visual information processing, whereas some newer antihistamines do not have these effects 7.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Diphenhydramine: Time to Move on?

The journal of allergy and clinical immunology. In practice, 2022

Research

Diphenhydramine: It is time to say a final goodbye.

The World Allergy Organization journal, 2025

Research

Tolerance to daytime sedative effects of H1 antihistamines.

Journal of clinical psychopharmacology, 2002

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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