predisone for my ferret

Question
Hello,
For some time one of my ferrets, stello, now age 3 1/2 would do his fair share of flattening out during play times. I had brought this up to the vet, at first with it being dismissed as fine and when i pushed they checked his blood glucose and it came back as 90, on the low, but normal range. so we never thought much else about blood sugar.
3 weeks ago he had surgery to remove a mast cell tumor, when he came home he was markedly different, sleeping all the time ( which i at first contributed to recovering) he would also become nauseous if you picked him up and carried him somewhere ( 'foaming' and pawing at his mouth ) so i brought him back to the vet. they did an xray and blood work.  his blood glucose was 61. his lungs were slightly inflammed, a very small amount of fluid in them but the vet said he didnt need medication for it and to just look out for any signs of coughing( which he doesnt do)  and his heart and lymph nodes looked normal.
stello has also had ibd, eosinophil gastroenteritis (didnt check the spelling..) we only found out because a few months after we got him he began vomiting. (We had our ferrets on evo the no grain/carb food but stello had a chicken allergy so we had to switch foods.) the vet thought it was impaction so they preformed surgery during which they found he had an enlarged lymph node (removed it) and ibd.  
he did well on his diet by totally ferret, a turkey venison and lamb formula but recently had a vomitting episode, im in the process of mixing his food with hills zd ( hes not a fan ) to try and help incase hes developed allergies to that food. (also feeding him "duck soup")

because of his low blood glucose the vet said prednisone was necessary. after 2 doses (1mg each) i noticed a huge difference, he was interested in play again, could move around easily and usually didnt have weak hind legs, walked straight and lasts 30-40 minutes before he flattens out. he tends to become restless or maybe uneasy and will sometimes hide under something and flatten out. no other symptoms, but i know he doesnt feel well..or is at least very tired. I grab him a blanket or bed and he cuddles up and falls asleep until he awakes again ready for more play. its been a few days since he's been on the prednisone and we took him back to get his blood glucose checked and it was 51.
the vet said if there is no improvement by next week she wants to raise the dose. im also noticing that the further he is away from the dose he recieved he starts to get the lethargy quicker and goes back to sleep with no interest in whats going on around him. (feeling fine once he gets the next dose)
So i figure the dose will get raised next week. my questions are.. if he's on 1mg now 2x a day .. what is considered a high dose? (when he's gone on flagyl for flare ups he gets 4mg (in one day). he weighs 2.6lbs )
My concern is this prednisone is just going to continually have to get raised. what is a high dose considered for his weight? what is considered 'long term' of being on this medication, how long before this medicine is going to effect his liver or cause ulcers? i know my little man still has joy and energy and play inside of him. last week i thought i might have to put him down but the medication has seriously brought his spunk back. (i think hes actually overly energetic-even for a ferret) but i dont want it to get to the point where im making him sicker in other ways or causing him pain.
also the process in which he takes his medicine is not stressful, i do it in pill form ( they only add sugars when they compound it) and mix it in with a turkey puree or "duck soup" and he loves it.
what are signs to look for if the prednisone is making him sick? I am not going to ask the life expectancy becuase I've read a lot of forums and blogs and I know my little guys days are numbered but i am hoping prednisone will help him out.
also i was wondering about him laying under things. if you try and talk to him he'll turn his head. i usually keep talking nice to him and he'll come out and lay his head next to mine. i wonder if hes depressed or just not felling well or both??  I had always thought maybe he had stomach aches becuase of the ibd. :( dont want my little guy in any pain

Answer
Hello Robin,

Wow, what a tough time your kid is having.  Poor guy!  I am thinking that the low glucose (insulinoma) is unrelated to the IBD, so your ferret has two separate problems.

Insulinoma is caused by pancreatic tumors that result in an over-secretion of insulin.  This causes the glucose in the blood to be absorbed, leaving less in circulation.  Low blood glucose results in symptoms such as "staring into space", foaming at the mouth, seizures, etc.  Unfortunately there is not much to be done with ferrets who have insulinoma.  Some opt for surgery to have the affected areas of the pancreas removed, but this is met with limited success.

On the other hand, eosinophylic gastroenteritis is indeed an allergic reaction, and most commonly to a protein such as chicken.  In fact, we are in the middle of a problem based learning course that just had similar case for a dog.  Apparently ZD is not such a great food for allergy, ESPECIALLY since chicken allergy is THE MOST COMMON, and yet chicken liver is the first ingredient.  Go figure, huh?  The problem is balancing the nutrition needs of a ferret (they need protein based diets with no carbohydrates; at least 45% protein and about 20% fat) with the hypoallergenic options available on the market.

Long term use of Prednisolone (months to years) can be detrimental to more than the liver.  It is a steroid that is basically a synthetic cortisol (which is what your adrenal glands secrete).  With prolonged use, the adrenal glands atrophy with disuse and it can have serious consequences.  Problems associated with long-term administration of prednisone relate to suppression of normal adrenal function, iatrogenic Cushing's Disease, liver failure and metabolic crisis due to abrupt withdrawal (always ALWAYS taper off of pred over the course of at least a week... sometimes months!!! never abruptly stop giving it).  Pred is also an immune-suppressant in high doses.

The only dosage I could find was in Plumb's Veterinary Drug Manual and it only had one entry for ferrets.  

As an antiinflammatory or for insulinoma (postsurgical or nonsurgical cases):

1.  0.5-2 mg/kg PO (oral) or IM (intra-muscular injection)

Assuming your ferret weighs 3 lbs (1.36 kgs), this dose range is 0.68-2.72 mg of prednisone.  This means you are at the mid to low range right now if you are giving 1 mg twice daily.  

As far as what to look for if pred is making him sick, any signs of jaundice (yellow-looking mucous membranes) to indicate liver problems, or a poor coat/skin which could indicate Cushings (though this may be difficult since food allergy is often expressed though the skin/coat as well as the GI tract).  The best way is to monitor his organ function though frequent blood work.  This will let both you and your vet know how his liver and other organs are holding up.

I hope this helps.  I'm glad my group just did a ton of research on this since our case with the dog was similar... it was a food allergy with prolonged use of pred over 3+ years that led to cushings and liver problems.    

You know your ferret better than anyone.  Pain can be manifested in many ways.  Some ferrets hide, others grind their teeth, while yet others will seek you out and want to be held.  The most important thing is mantaining a quality of life for these guys.  If you think he is in pain, do not hesitate to ask your vet for some meds to help with that.  Bupernex can be given orally, for example (it is unflavored... it is actually an injectable but can be given by mouth under the tongue.  It might offer him some relief.

-Cindy P.

Edit:  I want to clarify that prednisolone is basically the same drug as prednisone. There is a slight alteration in chemical structure but the two are used virtually interchangeably since one form is converted to the other in the body anyway.