Time to add another immune modulator or substitute

[srrice]

My 8 yr old sheltie was first diagnosed with IMHA Mar 19.  His PCV dropped to 18% while he was in a specialist's hospital.  The vets added Mycophenolate (100mg twice a day) to his prednisolone 20mg.  ((Also on Plavix, Nexium, B12.). His PCV rose to 26.  On Apr 13 the prednisolone was dropped to 15mg but the weaning has been stalled at this level.  His HCT has increased by only 1% since then and is now at 36.9%.  Is it appropriate to consider adding atopica and maybe dropping Mycophenolate?  I would love some suggestions to run by my vet....Thanks...

[Catherine]

Are you saying that your dog has been on the medication since 2019 or should that be 2021? How is he coping? He really needs to have the medication reduced. It may be that your dog has a normal HCT at the lower end of the scale anyway but he still needs to aim for coming off all medication eventually.

Here is a good medication protocol that your vet could follow:

Immunosuppressive Protocols for Oral Prednisolone in the Dog.
Ref: Clinical Immunology of the Dog & Cat by Michael J Day  – Professor of Veterinary Pathology, University of Bristol, UK and WSAVA - Chairman of Scientific Advisory Committee.

This example is based on a dog receiving an induction dose of 1.0mg/kg/q12hrs (every 12 hours).

Dose                Duration (based on clinical effect)

1.0mg/kg/q12h             10-28 days
0.75mg/kg/q12h            10-28 days
0.5mg/kg/q12h             10-28 days
0.25mg/kg/q12h                         10-28 days
0.25mg/kg/q24h                         10-28 days
0.25-0.5mg/kg/ Every other day      at least 21 days
0.25-0.5 mg/kg/ Every third day       at least 21 days

Azathioprine (a cytotoxic drug) can be used in combination with prednisolone at 2mg/kg/24 or 48 hrs and dose gradually reduced, when remission is achieved, over a period of months.
Clinical response to Azathioprine may take up to 6 weeks. (Plumb's Veterinary Drug Handbook)

Don't forget the gastroprotectant!

[Jo CIMDA]

Hi and welcome

I am sorry that your Sheltie has IMHA.  Was the original anaemia non-regenerative (destruction occurring in the bone marrow) or regenerative anaemia where the destruction of the red blood cells is most often happening in the spleen or liver?

My first instinct is that further immunosuppression is not needed because the HCT is only just below the reference range, so at this time the bone marrow is regenerating.   It is very reasonable to think that if the HCT is not increasing then more immunosuppression is needed but this is often the opposite of what is needed when a dog has been on high doses of preds for a longer period than usual. 

I have known several dogs to have been on immunosuppressive/high doses of prednsiolone for an inappropriate extended period of time (ie., longer than 3-4 weeks) and the weeks pass and the dog continues to be on a high dose of preds, this has caused the HCT to plateau.  I cannot say exactly why this occurs but in cases like this, when the pred is reduced the HCT starts to rise and normal levels are achieved. It may be a decreased release from the bone marrow as is seen with lymphocytes and eosinophils.

I notice that he is also on Nexium to protect his tummy from the excess acid that the preds produce.  Was he put on this at the start of treatment?  If not, was he put on this because he developed bleeding gastric ulcer, which would cause regenerative anaemia?

I presume your boy is also showing signs of drug induced Cushing's eg., pot belly, muscle weakness, hair loss thirst, hunger etc.,  These adverse signs should not be ignored and the medication should be reduced.  When treating something like IMHA with immunosuppressive drugs, and in particular prednsiolone, all clinical signs, including adverse effects of the drugs, and the blood results should be considered when making decisions about medication and dosages etc.  The good news is the side effects of preds do not affect smaller dogs/animals as badly as larger dogs.

'The goal of therapy is to use as much as is required and as little as possible for as short an amount of time as possible'.  Plumb's Veterinary Drug Handbook, 8th Edition. 

Personally I don't think added immunosuppressive treatment is necessary as your boy is also on Mycophenolate, and this should be providing sufficient immunosuppression, and a dog must not be on prednsiolone, especially at high doses for a very long time.   All immunosuppressive treatment dosage is designed to be reduced over a period of time. 

Below is the best example of a reducing immunosuppressive protocol I have come across. It is an excellent guide and can be adjusted to the individual.

I hope this information helps

Jo


Taken from my seminar notes:

Example: Reduction Protocol for prednisolone:
Clinical Immunology of the Dog & Cat , 2nd Edition,  by Michael J Day
Professor Michael DayBSc, BVMS(Hons), PhD, DSc, DiplECVP, FASM, FRCPath, FRCVS 

Professor of Veterinary Pathology, University of Bristol, UK and WSAVA - Chairman of Scientific Advisory Committee.
This example is based on a dog receiving an induction dose of 1.0mg/kg/q 12hrs (q = every)
Dose                           Duration (based on clinical effect)
1.0mg/kg/q 12h                          10-28 days
0.75mg/kg/q 12h                       10-28 days
0.5mg/kg/q 12h                         10-28 days
0.25mg/kg/q 12h                        10-28 days
0.25mg/kg/q 24h                        10-28 days
0.25-0.5mg/kg EOD                    at least 21 days
0.25-0.5 mg/kg every third day      at least 21 days

Every reduction is made after consideration to improvement of clinical signs, blood results and side effects of the drugs.
Prednisolone:  "Doses above 2.2mg/kg/day do not give more immunosuppression but do cause more side effects. Many internists believe that prednisolone doses should not exceed 80mg per day, regardless of the dog's weight."  Plumb's Veterinary Drug Handbook Eight Edition.

Note: High doses of steroids must not be stopped abruptly.  Your dog could go into an adrenal crisis if the medication is withdrawn too quickly. 

Reducing the Tablets
When significant improvement in the dog's condition is seen, usually between 10-28 days, the initial steroid dose is usually reduced by 25%. The dose is generally given for another 10 - 28 days and depending on the dog's progress and clinical signs the dose is significantly reduced once more for a further 10-28 days; and again in another 10-28 days. Anecdotal evidence has shown that if at this stage the dose is lowered more slowly, or reduced to an every other day dose over a period of months rather than weeks, relapse are less likely to occur.  It is always tempting to get your dog off steroids as soon as possible, but when treating autoimmune disease, as long as the dog is on a low, every other day dose then taking the last stage slowly seems to work best, depending, of course, on the severity of the disease and allowing for the difference in individual response - no two dogs reactions are exactly the same.  With some autoimmune diseases such as SLE, the dog is likely to be on steroids for the rest of his life. Usually an every other day dose can be achieved, but you risk a relapse if you take the dose too low.
Notes:
In addition to immunosuppressive drugs he should have something to protect his stomach from excess acid.  The last thing your dog needs when he is feeling poorly is a bleeding stomach ulcer caused by the drugs.  Sometimes, Antepsin is given to coat and protect the stomach (but this must not be given within two hours of other medication otherwise it will stop the drugs from being absorbed. Another gastroprotectant used is Omeprazole. To minimise irritation to the stomach it is usual for the daily dose of steroid to be split into two doses and given with food, one dose in the morning with breakfast and the other dose with his evening meal. I have known several dogs, who did not receive a gastroprotectant as a part of their treatment regime, and went on to develop anaemia. This is not autoimmune haemolytic anaemia but iron deficiency anaemia caused by bleeding stomach ulcers. Using a gastroprotectant is a good preventative measure. When the steroids have been significantly reduced to a low dose, a gastroprotectant may not be necessary.
Excess acid, produced because of the drugs, may make a dog prone to developing pancreatitis. A dog with pancreatitis will appear in pain and his back may be arched as if he can't straighten up.  He may be lethargic, seem bloated and have a tender abdomen. Dogs usually go off food and water, may vomit and look depressed.  If you suspect that your dog has pancreatitis, don't try to feed him because it will make the condition worse. Take him to the vet as soon as possible as he may require treatment or need to go on an intravenous drip to stop him dehydrating.  Again, the risk of pancreatitis should be minimal once the dog is on a lower dose of steroids.   A low fat diet is best when your dog is on high dose steroids or prone to pancreatitis. 
As your dog's immune system is being significantly suppressed, he will be more likely to pick up infections, and will not have the ability to fight against them.  As a precaution a broad spectrum antibiotic is often prescribed. Also it is sensible not to exercise him in areas where he is more likely to encounter infections, for example, a park or a popular dog walking area. 
Whilst your dog is on high dose steroids he will want to eat and drink excessively. However, this also means that he will want to urinate more and this can sometimes cause temporary incontinence.  You may have to get up to let him out during the night and if you leave the garden door open during the day, it may save some mopping up!  He cannot help it and won't like it either, so don't be too hard on him, it's only temporary. You will notice as he is weaned off the drugs the unwanted side effects will subside and he should return to normal habits and behaviour.  Urinary tract infections and/or bacterial skin pustules are not uncommon when a dog's immune system is suppressed, and this is often the reason for a dog to be off colour during this time.  Note: Always consider a urine infection if your dog seems under par.  A course of antibiotics will usually sort this out quickly.
Depending on what autoimmune disease your dog has, he will probably need to have regular blood tests.  Biochemical blood tests will also keep an eye on other body functions, such as those of the liver and kidneys, which is important at this stage.
Assuming good progress is being made, the clinical signs of his illness are diminishing and positive signs of improvement are apparent, your vet will want to start weaning him down from the high doses of steroid.  This process can take 3-6 months or more, and usually begins any time after 10 - 28 days from the start of treatment, depending on the results of his blood tests and his clinical signs.
Relapses are not uncommon, especially in diseases that are difficult to control, for example SLE.  A relapse may mean that initially, your dog needed to be on a higher dose of immunosuppressive drugs for a longer period of time, or your dog may have been weaned off a little too quickly and then the dose withdrawn too soon.
If a relapse occurs he will probably show similar clinical signs to his initial crisis.  He will have to go back on an immunosuppressive dose of prednisolone, but it may not have to be quite as high as before. A combination drug may need to be added at this stage. The weaning process will then have to start all over again. Returning to an immunosuppressive dose will mean that he has to go back on a gastroprotectant.

Side Effects of the Drugs – Iatrogenic Cushing's Syndrome
Iatrogenic Cushing's syndrome is a side effect of high dose steroids and is caused by too much corticosteroid in the body. To a lesser extent, the immediate side effects observed when the dog initially goes on steroids eg., drinking, eating and urinating excessively is a mild example of Cushing's syndrome.  Personally I like to see dogs responding to high doses of prednisolone in this way, as it means that they are responding to the drugs as they should.
Usually, Cushing's syndrome only becomes a real problem when exceptionally high doses, or prolonged high doses of steroids are administered, maybe due to a relapse, or in some cases where the vet is inexperienced in reducing steroid doses and keeps the dog on a high dose for longer than necessary; or when the dog is not responding to treatment and higher doses are necessary to control the disease.  This is where the cytotoxic drug Azathioprine, and other more recently used, immunosuppressive drugs are very useful. 
All drugs carry side effects and Azathioprine is no exception, but it does not carry the same side effects as prednisolone, therefore by using this drug in combination with prednisolone it reduces the risk of iatrogenic Cushing's syndrome.  As Azathioprine takes at least 10 days to take effect, starting the 'combination' therapy at the beginning of treatment may enable the prednisolone to be lowered within the 10-28 day band and still maintain a good level of immunosuppression. If your dog is not responding to treatment then your vet may consider changing his treatment to other immunosuppressive drugs.

How Can I Tell if My Dog Develops Iatrogenic Cushing's Syndrome?
Iatrogenic means 'drug induced'.  Clinical signs of Iatrogenic Cushing's syndrome are the same as primary Cushing's syndrome but can present with acute clinical signs. It reflects the level of corticosteroid in the body.
The most notable side effects are, heavy panting, some hair loss, and an increase in drinking and urinating, excessive pigmentation.  This is something everyone seems to be aware of and accepts as normal when a dog is on high dose steroids. Very often the dog will be weaned down to a low dose before any major problems arise. 
Acute Cushing's syndrome due to overdosing of corticoid steroids can be very serious.  Blood results will reflect this, especially the liver enzymes which may be extremely high. Red blood cells and blood platelets may also be high and blood clotting may be a risk.
So when should you alert your vet to suspected, unacceptable level of corticosteroid?  The owner should take note when other clinical signs occur, such as: Depression, anorexia, muscle wasting and extreme weakness, continuous panting, lethargy - unwillingness to exercise, skin lesions and thinning of the skin, excessive hair loss, pot-bellied appearance and sagging back, behavioural changes (aggression).
If your dog is showing these signs it will probably mean that the dose of steroids needs to be lowered. It is important that it is not confused with a relapse of the dog's condition or an infection. The dilemma is that steroids must not be withdrawn too quickly otherwise the dog may go into an adrenal insufficiency crisis.  If the clinical signs of iatrogenic Cushing's syndrome is intolerable, it is hoped that the high dose of steroids that he has been on will have already done their job and that his autoimmune disease will be stable. As long as the steroids are lowered in a controlled manner and in time, all the symptoms of Cushing's will subside and your dog will return to normal, but extreme signs must not be ignored.