In a pediatric patient (2-14 years) with an allergic reaction, what is the IV/IO diphenhydramine dose?

• A. 0.5 mg/kg IV/IO
• B. 0.75 mg/kg IV/IO
• C. 1 mg/kg IV/IO not to exceed 25 mg
• D. 2 mg/kg IV/IO

Answer: (C)

Diphenhydramine in a pediatric allergic reaction is given using weight-based dosing with a safety cap. For a child between 2 and 14 years old receiving IV or IO administration, the dose is 1 mg per kilogram of body weight, not to exceed 25 mg total. This approach ensures the dose is appropriate for the child's size while avoiding excessive anticholinergic effects and other adverse reactions. In this situation, epinephrine is the first-line treatment, and diphenhydramine serves as an adjunct to help with histamine-mediated symptoms. Doses like 0.5 mg/kg or 0.75 mg/kg would be under-dosing, while 2 mg/kg would surpass the safe maximum.