Hi Cara!
 
Very scary when they scream - I am sure you will hear from others, but
what your ferret experienced is a seizure caused by lack of sugar in
the brain.  (or at least how it's been described to me).
 
Here's the link to FACT's insulinoma article on our website.
http://www.ferret-fact.org/Insulino.htm
We have never nor have we ever been recommended to use ferretone - the
issue is that the ferret needs digestible sugar as provided by protein
and the best way to get them that is via their usual high protein food.
 
Older ferrets usually do not eat properly.  Bad teeth, mild senility,
whatever - not unlike elderly humans, they just don't eat properly.  So
we have found that in addition to medication (be it prednisone or azium
drops; or in more severe cases, proglycm) the key to keeping level blood
sugar (as in diabetics) is small, frequent meals.  As dry food is usually
harder to have senior ferrets eat in adequate quantities, duck soup or
"gruel" is the treatment of choice.
 
"Lucky Duck soup" is great for the elderly... but dependent upon the
recipie can be a PAIN to put together.  Better to put your efforts
into attempting to feed frequently.  I shoot for every 4 hours --- but
realistically with folks who work, that is not always possible.  Just
do the best you can.
 
As for "gruel" we just take ferrets regular food; grind it in a coffee
grinder; (we do a whole coffee can at a time); add water and microwave
to a cream soup consistency.  (The shelter does a fresh batch daily -
for 1 to a couple of ferrets, you can pre-make and keep refrigerated for
2 to 3 days and reheat {addiong water} as needed).  Don't underestimate
the amount of water to add!  It's about a 1 part food to 3 parts water
ratio -- depending upon the food.  Serve about 2 ounces at a time at baby
formula (warm, not hot) temp.  Each ferret can be rather picky as to
consistency and termperature (they are ferrets, after all!).
 
Most ferrets love it.  Some refuse it.  For the later, you may need to
sweeten a bit to get them to take it (then kill off the sugar!) or add
some ferretone for your ferret to at least try it.  I have younger
ferrets that will stomp anyone in their path to reach the bowl.  :)
 
It is horrid for their teeth, as it is soft,.  watery food....but it is
far better than the alternative..
 
I am sure you will receive other good information here.  But the above is
how FACT (and I) work with out insulinoma ferrets.
 
Best wishes
 
Ann Gruden
Ferret Assn of CT, Inc.
[Posted in FML issue 5183]