DiphenhydramineHCL tends to concentrate in fluid around the brain in young children and can have unpredictable results in infants and toddlers, he says.
BBC: Should parents drug babies on long flights?
2.
Take the drug marketed in the US as Benadryl, diphenhydramineHCL (quite different from the product known as Benadryl in the UK, which is the drug cetirizine).