My 2 1/2 year has an allergic reaction to keflex has hives all over body how much benedryl can i give her she is 28 lbs ?

Benadryl (diphenhydramine) dosing: Benadryl (diphenhydramine) is effective between 0.5 to 1.0 mg/kg per dose every 8-12 hrs. Based on pt being 28 lbs then a tspn of benadryl (diphenhydramine) 12.5mg/5ml will give pt 12.5 mg which is about 1 mg/kg.

Yes: You sure can - 6.25 mg every 4-6 hours. Make sure she is not having troubles breathing or swallowing. Then it is ER and steroids!