What is the dosage amount of children's Benadryl to give a 4 year old child who weighs 30 lbs?

The Hat Man is a fictional figure that started appearing on certain internet sites in the early 2000s that has recently been referred to as the “Benadryl Hat Man” after reports of people hallucinating and sighting him after overconsumption or abuse of Benadryl. Most of these reports have appeared on Reddit or the image-based bulletin site 4chan. Continue reading

The maximum safe Benadryl (diphenhydramine) dose for adults is 50 to 100 mg for a single dose with a daily maximum of 300 mg in 24 hours. However, your safe Benadryl dose depends on your medical conditions, age, previous tolerance to diphenhydramine, other medications you take, weight and body size, what condition you are using Benadryl for.

The maximum oral dose of diphenhydramine for adults is generally reported as 50 to 100 mg for a single dose or no more than 300 mg in 24 hours, but this can vary depending on what condition diphenhydramine is being used for, the salt of diphenhydramine used (there are two salts available in the US diphenhydramine citrate and diphenhydramine chloride), the age of the person, how much diphenhydramine they have tolerated before, and if they are on any interacting medications. Taking too much diphenhydramine can be fatal.