Older antihistamines, also called first-generation antihistamines, such as benadryl diphenhydramine , vistaril hydroxyzine , or chlortrimeton chlorpheniramine , are considered [...]

We noticed his strange behavior about an hour after we gave him the benadryl and induced vomiting, but it already dissolved into his system.

If you will be taking benadryl regularly, tell your doctor about any underlying conditions or medications that you are taking.