Treating Small-Breed Addison's Dogs with Low Doses of Prednisone or Prednisolone

My 4-year old Toy Poodle was diagnosed with atypical Addison's disease about 6 weeks ago. She weighs 11.8 lbs and is taking 1.25 mg of prednisolone per day. She is not receiving any mineralocorticoid supplementation (i.e., Florinef or Percortin-V) for now since her serum sodium and potassium levels are in the normal range. We will continue to monitor that because we know that that might change and mineralocorticoids will have to be added to her treatment.

For her glucocorticoid needs, we are using a 5-mg tablet of prednisolone that we cut into quarters to administer a 1.25-mg dose each day. This is extremely tricky, and there is probably never a day that she gets an exact dose because the tablets do not cut without some crumbling.

So I have two main questions:

1. First, my dog has developed a ravenous appetite and finishes her meals very quickly. Normally, she has a picky appetite. I know that you generally recommend giving these dogs a much lower dosage, and that a lower dosage would be better for her overall health since she will be on this daily dosage for the rest of her life. Should her prednisolone dosage be lowered to help with the appetite issue? 
2. Second, is there any other tablet or form of prednisolone that would be easier for us to administer to her so that she gets the proper amount each day? The 5-mg tablet just isn't working very well for us. 

Thank you for your help.

My Response:

The glucocorticoid replacement dose I use for prednisone or prednisolone in dogs with Addison's disease is 0.1-0.2 mg/kg/day. So at 11.8 pounds (5.4 kg), that calculates out to be only 0.5 mg/day, up to a maximum dose of 1.0 mg/day. So if you are giving your small dog 1.25 mg/day, that means you are giving too much of the drug. That would certainly be enough to induce iatrogenic Cushing's disease, as reflected by the increased appetite.

In dogs, prednisone is converted to prednisolone within the body. So basically, these two glucocorticoids can be used interchangeably.

I would try to lower the daily prednisone/prednisolone dose down to 0.5 mg each day. Administrating too much glucocorticoid will cause increased hunger (as you see in your dog).  Overdosage of prednisone, prednisolone or any other glucocorticoid can also lead to lethargy, weight gain, enlargement of the abdomen, muscle atrophy, and muscle weakness. Decreasing the dose of the prednisone or prednisolone should help prevent any of these problems.

Fig. 1: Prednisone is available as a 1-mg tablet

Fig 2: PrediapredOral prednisolone
liquid (1 mg/mL) 

Prednisone tablets are available as 1-mg and 2.5-mg sizes, which can be helpful in dosing small to medium-sized dogs (Figure 1).

In addition, both prednisone and prednisolone are available as a syrup/oral liquid or solution, available as a 1 mg/mL concentration (Figure 2).  Examples of liquid prednisolone products include Pediapred® (Celltech Pharm); Millipred® (Laser); Orapred® (Sciele); Veripred® 20 Hawthorn); and Flo-Pred® (Taro). For prednisone, Intensol® Concentrate (Roxane) oral solution is available.

All of these formulations are human-labeled products so your veterinarian may not be familiar with them. Your local pharmacy will know about them, however.

Either way, I'd get either the 1-mg tablets and give half a tablet a day. Or use a liquid formulation (1 mg/mL) and give 0.5 mg (1/2 mL per day).

References:

1. Plumb, DC. Plumb's Veterinary Drug Handbook. Seventh Edition, Wiley-Blackwell. 2011.