Just to let everyone know, I followed the advice of another person and
called United Vaccine Co. (makers of Fervac) to find out if they recommend
Benedryl or if having the vet administer a cortisone shot would be better.
The answer I got from their customer service line is that "I am sorry, we
do not give out that kind of information, you need to talk to your vet."  I
was then told that the on-staff vet would call me back, but they never did.
This seems pretty irresponsible to me, considering it is their product.
 
I am happy to report that I went the "safe" route and paid the extra to
have my vet pre-medicate with cortisone, and there were no bad reactions.
All ferrets were up and about, as if a shot never took place.  I am
watching for reactions the rest of the day, but it has been three hours
and no problems (not even the usual sleepiness).
 
In the ten years of ferret ownership, I never pre-medicated and never had
a bad reaction to Fervac, but because of all the bad things I have been
reading lately, I decided not to risk it.  I also talked to the USDA about
Fervac and was told that there are NO studies that prove Fervac is to blame
for this, BUT he did tell me that if your ferret does experience a bad
reaction, to have your vet report it ASAP.  Apparently, they are TRYING
to track these situations.
 
Just wanted to share what I learned today, and also let whoever it was that
posted about calling United for recommendations that they do not tell you
anything other than "check with your vet." Don't waste your time on them.
[Posted in FML issue 3035]