Prednisone

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Prednisone is a synthetic corticosteroid and is part of a group of glucocorticoid drugs. It is  activated by the liver to become prednisolone.  Prednisone is  often called the “cornerstone”  for the treatment of AIHA/IMHA and is used in the early stages in very high doses to stop red cell destruction. It can take roughly 5-7 days to have an effect.  Prednisone can also be used  for many other inflammatory & allergic conditions.

Prednisone doseage for AIHA/IMHA is normally 1mg per pound (2mg per kilo) per day & should be divided into in 2 equal doses, given 12 hours apart.  Sometimes, an even higher dose may be prescribed if the PCV/HCT is very low.  If a case is particularly acute (rapid onset), injectable dexamethasone may be used  during the initial stages (“stronger” than prednisone) until oral prednisone can be given.

If any kind of infection is suspected, however small the suspicion may be, high dose antibiotic therapy should be started immediately as the immune system is seriously compromised (weakened).  Prednisone’s anti-inflammatory action makes it impossible for your dog’s immune system to fight off infection. Long-term high dose therapy with antibiotics is recommended on suspicion or confimation of certain infections  such as tick borne diseases.

Some veterinarians will immediately add another longer (slower) acting immuno-suppressant (cytotoxic) drug such as azathioprine or cyclosporine to the treatment protocol, others will sometimes wait for a week or so. Predisone should NOT be given on it’s own for longer periods to dogs with non-regenerative AIHA/IMHA – it is absolutely essential to add a long acting immuno-suppressant into the treatment protocol for the best chance of a successful outcome.

Diabetic dogs need to be very carefully monitored if taking prednisone which should only be given in life threatening conditions.

Stomach protection (e.g. sucralfate, famotidine) is recommended to prevent irritation & possible ulceration, but must be given at a completely separate time from other drugs otherwise they can stop proper absorption of the full dose.

Side effects are unavoidable with high dose prednisone, especially in the long term.  Short term side effects include panting, increased thirst & urinating (peeing), weight gain, dehydration, muscle wasting  despite larger appetite, increased blood sugar levels, increased risk of bladder & other infections, inability of wounds or sores to heal .  Encouragement to drink plenty of water is recommended.  The use of a syringe full of water (without the needle of course!) gently placed in the corner of the mouth will aid re-hydration if you think your dog is not drinking enough. Longer term side effects can include liver toxicity (hepatoxicity), osteoporosis, severe muscle wasting & weakness (atrophy), poor coat, inability of wounds or sores to heal which can become worse, calcinosis cutis & darkening of the skin.  Milk thistle (Silybum marianum) has been found helpful in the reduction in abnormally high liver enzymes and some vets will prescribe it. As prednisone is an essential part of the treatment of AIHA/IMHA, we have to cope with these side effects as well as we can, accepting that to some extent,  our dogs will suffer some or all of them.

Weaning or tapering. Suppression of the adrenal glands  occurs as quickly as 7 days after taking prednisone.  It is therefore very important to gradually reduce the doseage – the very slowly & carefully rule will usually prevent a relapse or Addisonian Crisis (see glossary).  Never stop the prednisone dose completely unless told to do so by your vet (this would only happen in exceptionally unusual circumstances) . In an ideal situation, slow reduction will achieve complete withdrawal of the prednisone, although some dogs will require a life-long maintenance dose.  The usual & safest reduction is  20-25% per month.  It is important to take a blood test both BEFORE & AFTER each reduction to monitor PCV/HCT.  If a significant drop in HCT/PCV is seen, the dose will normally be increased to the previous amount to achieve a stable condition once more.

In short, prednisone is an essential & unavoidable part of AIHA/IMHA treatment.  It must be given at a high enough dose to be effective & must never be withdrawn quickly.  If infections are not adequately treated, they may become much worse during predisone therapy & could prove fatal.

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