Dr. Ruth no longer pretreats with Benadryl as a rule, because she's
seen a decent number of ferrets react despite being pretreated with it,
and also because some ferrets react to the Benadryl itself. Instead,
she pretreats with dexamethasone. To read her words on the topics, see
http://ferrethealth.org/archive/FHL2771.
It may be worth asking your vet to follow Dr. Ruth's protocol, since
she reports a reduction in reactions with it.
[Posted in FML 6414]