What is the FDA-approved dose of diphenhydramine (Benadryl) for children?

FDA-Approved Diphenhydramine Dosing for Children

According to FDA guidelines, diphenhydramine is not approved for use in children under 6 years of age, while children 6-12 years should receive 10 mL (25 mg) every 4-6 hours, and children over 12 years can receive 10-20 mL (25-50 mg) every 4-6 hours, not exceeding 6 doses in 24 hours. 1

Age-Based Dosing Recommendations

• Children under 6 years: Do not use 1
• Children 6 to under 12 years: 10 mL (25 mg) every 4-6 hours 1
• Children 12 years and older: 10-20 mL (25-50 mg) every 4-6 hours 1
• Maximum frequency: Do not exceed 6 doses in 24 hours for any age group 1

Weight-Based Dosing Considerations

• For clinical settings where weight-based dosing is preferred, the American Academy of Pediatrics recommends 1-2 mg/kg per dose with a maximum single dose of 50 mg 2, 3
• Children weighing more than 40 kg should be dosed as adults 2
• For acute hypersensitivity reactions, the recommended dose is 1-2 mg/kg 3

Safety Considerations

• Common adverse effects in pediatric patients include tachycardia, hallucinations, somnolence/sedation, agitation, and mydriasis 2
• Diphenhydramine should be avoided in patients with severe renal impairment (creatinine clearance <10 mL/min) 2
• Diphenhydramine should be considered second-line therapy to epinephrine in anaphylaxis and never administered alone for this indication 2, 3
• Pharmacokinetics differ significantly by age - children have a shorter half-life (5.4 hours) and higher clearance rate (49.2 mL/min/kg) compared to adults 4

Special Precautions

• Patients experiencing changes in behavior beyond mild drowsiness should be referred to an emergency department 5
• Children under 6 years who accidentally ingest at least 7.5 mg/kg should be referred to an emergency department 5
• Children 6 years and older who ingest at least 7.5 mg/kg or 300 mg (whichever is less) should be referred to an emergency department 5
• Topical diphenhydramine should be used with extreme caution in children, as fatal cases of toxicity from dermal absorption have been reported 6

Administration Considerations

• Oral liquid formulations are more readily absorbed than tablets when used for acute allergic reactions 3
• For parenteral administration (IV/IM) in emergency settings, the dose remains 1-2 mg/kg with a maximum of 50 mg per dose 2