What is the recommended dosing for Benadryl (diphenhydramine) in pediatric patients?

From the Guidelines

Benadryl (diphenhydramine) dosing for pediatric patients should be 1 to 2 mg/kg per dose, with a maximum dose of 50 mg IV or oral, as recommended by the most recent guidelines 1. The dosing is based on weight, and it is essential to use the most accurate weight-based dosing possible to minimize the risk of adverse effects.

• For pediatric patients, the recommended dose is 1 to 2 mg/kg per dose, which can be administered orally or intravenously.
• The maximum dose should not exceed 50 mg per dose.
• It is crucial to note that diphenhydramine is not recommended for infants under 2 years except under physician supervision due to potential respiratory depression risks.
• Liquid formulations are preferred for younger children who cannot swallow tablets.
• Parents should be aware of common side effects, including drowsiness, dry mouth, and potential paradoxical excitation in some children.
• Diphenhydramine works by blocking histamine H1 receptors, reducing allergic symptoms like itching, sneezing, and hives, but its sedating properties result from its ability to cross the blood-brain barrier and affect the central nervous system. The guidelines from the National Institute of Allergy and Infectious Diseases (NIAID)-sponsored expert panel 1 provide the most recent and highest-quality evidence for the dosing of diphenhydramine in pediatric patients.
• These guidelines recommend using diphenhydramine as an adjunctive treatment for anaphylaxis, in addition to epinephrine and other therapies.
• The guidelines also emphasize the importance of using weight-based dosing and monitoring patients for potential adverse effects.

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 age/dose Adults and children over 12 years of age 10 mL (25 mg) to 20 mL (50 mg) Children 6 to under 12 years of age 10 mL (25 mg) Children under 6 years of age Do not use

The recommended dosing for Benadryl (diphenhydramine) in pediatric patients is:

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

From the Research

Pediatric Benadryl Dosing Considerations

• The recommended dosing for Benadryl (diphenhydramine) in pediatric patients is not explicitly stated in the provided studies, but general guidelines for pediatric dosing can be applied 3, 4.
• Pediatric patients require individualized dosing based on their age, size, and level of organ maturity, rather than simply administering a "small adult" dose 3.
• The approach to pediatric drug dosing should be based on the physiological characteristics of the child and the pharmacokinetic parameters of the drug 4.
• For children under 2 years old, the volume of distribution (V(d)) may be altered, and hydrophilic drugs with a high V(d) in adults should be normalized to body weight, whereas hydrophilic drugs with a low V(d) in adults should be normalized to body surface area (BSA) 4.
• After 6 months of age, BSA is a good marker as a basis for drug dosing, but drugs that are primarily metabolized by cytochrome P450 2D6 and uridine diphosphate glucuronosyltransferase should be normalized to body weight 4.

Safety Considerations

• Diphenhydramine can cause paradoxical central nervous system stimulation in children, with effects ranging from excitation to seizures and death 5.
• Fatal intoxications in young children have been reported, with postmortem blood diphenhydramine levels lower than those seen in adult fatalities 5.
• The adverse side-effect profile of diphenhydramine is higher among children and older adults, leading to restrictions on its use in some countries and recommendations to use second-generation antihistamines instead 6.
• Medication dosing safety is critically important in the Emergency Medical Services (EMS) setting, and weight-based dosing in pediatric patients can increase the risk for harm when dose calculations are inaccurate or incorrect 7.

Best Practices

• Modification of dosing should be based on response and on therapeutic drug monitoring 4.
• A dosage guideline for drugs that are significantly excreted by the kidney should be based on the determination of renal function in the first 2 years of life 4.
• Standardization of medication formularies and the use of technologies that enhance dosing safety can help reduce the risk of medication errors in pediatric patients 7.