Actually Pheylpropanolamine (PPA) was the nasal decongestion medication
that was taking off the market by the FDA.  Sudafed (AKA pseudoepherine
hydrochloride) is the only one still on the market!
 
Please be careful if you give over the counter medications to your ferrets.
A lot of the allergy medications have a nasal decongestion medication
(pseudoephedrine) and/or a head ache medication (tylenol/actetaminophen
or ibuprofen) in them.  Tylenol can be fatal to ferrets (and cats)!
 
Please only use plain Benadryl without anything in it (just plain
diphenhydramine).  Chlor-trimeton is another antihistamine, but again you
want the one without anything else (just plain chlorpheniramine) in it.
Yes, as X pointed out some ferrets will suffer from seasonal allergies
(spring and fall) just like people with allergies do.  Plain Benadryl can
be used for ferrets with allergies.  Again make sure it is just plain
Benadryl and not a combination product.  Like wise if you are giving
Benadryl before vaccines, make sure it is the plain benadryl.
 
Hope that clears up the confusion,
Jerry Murray, DVM
[Posted in FML issue 3433]