Medications for Addison’s Disease

There are a number of medications available, but I’m just going to cover the main ones that I’m familiar with. There are injectable versions of some drugs commonly given in pill form, which are used at veterinary offices for dogs that are in a crisis or that cannot keep food down. You wouldn’t use those at home so I’m not going to cover them in detail.

Because Addison’s is so uncommon, the ideal treatment protocols for it are still being learned. Even many veterinarians aren’t familiar with all the medications or current dosage protocols. Some even have incorrect information. It doesn’t make them bad vets, it’s just that, as I said, proper treatment protocols are still being learned and many vets can go their entire career without treating a single case of Addison’s. This is where learning yourself and being your dog’s advocate becomes so important.

Fludrocortisone

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Generally sold under the brand name Florinef, although generic brands are also available. In some countries the generic is the only available option. For those whose dogs can metabolize Fludrocortisone, they seem to like it. It means your dog doesn’t need an injection every month. The starting dose for Fludrocortisone is generally lower than what most dogs require. Dogs in general tend to metabolize Fludrocortisone quite poorly, and most will require an increase in the dosage over time with many becoming completely resistant to it. Suki was initially started on two tablets of Florinef, one with breakfast and one with dinner, and was up to six with a worse electrolyte panel than pre-diagnosis by the time I made the call to switch her medication.

Fludrocortisone has some glucocorticoid activity, equivalent to roughly 0.25mg of prednisone per tablet, so most dogs do not require any additional medication if they are on Fludrocortisone. Often vets will prescribe additional Prednisone at the beginning of treatment, or if the dog is going to have surgery. Some vets (often more than there should be) will want the dog on Fludrocortisone plus additional Prednisone for life.

Fludrocortisone is generally kept in the fridge, but check your container as some are stored at room temperature.

Desoxycorticosterone pivalate

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Or DOCP, which is what I’ll refer to this as from here out because I can barely even pronounce the full name much less write it out multiple times. Sold under the names Percorten-v (the ‘-v’ meaning veterinary) and Zycortal. The only difference between the two is the carrier liquid and the preservative. A few dogs have reacted poorly to Zycortal, but overall there is zero difference in the reaction between the two. Dogs can be switched from one to the other without needing the dose adjusted. Outside of North America Zycortal is the only available option.

The initial cost of DOCP is much greater than Fludrocortisone, but it lasts longer so the cost per month is often much lower. Injections are generally between 25-30 days, with most dogs settling around day 27. Even at a mid-high dose a bottle lasts Suki 8-10 months. Because Suki had such a bad time on Florinef I wanted to guarantee she was going to feel better, so I went with Percorten because there has never been a reported reaction to it. So many dogs are doing excellent on Zycortal though that next time though I will likely give it a try. At the time of writing this Percorten isn’t being manufactured so I may not have the choice anyway.

The manual for Percorten states that it should be injected into muscle (instramuscular, or IM), while the manual for Zycortal states to inject it under the skin (subcutaneous, or subQ). Both, however, can be given subQ and most dogs taking Percorten get it this way. Most pet owners find subQ injection easier to give at home.

Dosing of DOCP is often much higher than what dogs need. The current recommended starting dose is 2mg/kg, but many dogs do excellent on 1mg/kg and often are even lowered further. The initial dose is based on weight, then all future doses should be based on electrolyte results. Give the first dose, test around day 14 to make sure it’s working, then test again between day 25-27 to assess when to give the next injection. You want to find an injection day between 25-30 days, adjusting the dose to find your dogs optimal amount. The injections should be given when the potassium (K) value is near the higher end but still not above normal, which is generally 4.8 on most tests. Because DOCP is so effective, if it’s given too early or in too high of a dose it can cause the potassium to drop to below normal levels. It won’t kill your dog, but it will make them feel unwell and the goal of giving DOCP is to make them feel healthy.

Both Percorten and Zycortal are stored at room temperature. Or more accurately a cupboard with a moderate temperature. They’re like Goldilocks, liking it not to hot and not too cold.

Prednisone and Prednisolone
This replaces the Glucocorticoids, mainly cortisol. I’m putting these together because they’re basically the same thing. Prednisone is metabolized in the liver and converted to prednisolone. Prednisolone skips this step, taking some work off the liver which makes it especially good for dogs with elevated liver enzymes. If your dog is on DOCP they will also need prednisone or prednisolone every day. Some veterinarians will prescribe every-other-day dosing, but daily is better because it mimics the body’s normal routine. Healthy adrenal glands produce a surge of cortisol right after waking up, and it gradually decreases in amount throughout the day.

When people hear Suki is on prednisone, daily, for life, they tend to get very serious. They’ll tell me prednisone isn’t supposed to be used long-term. Its reputation for nasty side-effects is generally known due to it also being used as an immune-suppressor for allergies or other autoimmune disorders. That’s in dogs with functioning adrenal glands though, and the reason it shouldn’t be used long-term is because it can cause Addison’s (if you give those hormones, the adrenal glands don’t need to produce them anymore and will atrophy). I like to compare it to insulin. Diabetic dogs need daily insulin because they don’t produce it themselves. Addison’s dogs don’t produce cortisol (prednisone), so they need to take it supplementally.

Provided they’re on the dose they need to mimic their natural levels there should be no side effects in dogs with Addison’s, and side-effects are a sign the dose is too high. Signs that the dose is too high include excessive thirst, incontinence, panting, lethargy or hyperactivity, fluid retention, muscle loss, anxiety, and aggression or irritability. Long-term use of a high dose can suppress the immune system leading to infections, hair loss, and skin darkening. At a biological dose prednisone will not stress an Addison’s dog’s liver, but if given in excess for long periods of time it can. It’s important to get your dog on an appropriate dose. Some veterinarians are resistant to reducing prednisone and believe the side-effects are just part of treatment, which is when it’s important to be your dog’s advocate. One of the most frustrating things was just being told breeds like Suki’s can have coat troubles. This wasn’t normal. This is a sign that something isn’t right.

 

Most dogs are over-prescribed prednisone, but it’s important to remember than in the end you, as your dog’s owner and advocate, control how much your dog is given. I’d like to add this doesn’t make a vet bad. They can only go off what they’re taught and what the drug companies recommend. Going off label can be risky because if something goes wrong, they’re liable. Suki was prescribed 2.5mg of prednisone each day. I lowered it. She currently takes 0.5mg, is doing better than ever, and may even require less over time. Her hair is growing back, and the new fur is wonderfully soft and shiny black. She’s also gained back almost all the muscle that she lost. Dosage isn’t an exact science because the end goal is to mimic exactly what your dog’s adrenal glands would produce on their own. A higher dose will need to be given before surgery. In times of stress or during very long hikes they may also require a small boost of prednisone. They may also need a higher dose during hot weather. On hot, humid days I’ve boosted Suki to 0.75mg or even 1mg. Remember, the goal is to replace whatever amount your dog needs. No more, no less. So while you don’t want to give too much is also isn’t a contest to see who can get their dog on the lowest dose. Go by your dog’s symptoms, and if they need more then they need more. The proof will be in how your dog acts and looks.

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Some vets will prescribe prednisone dosed every other day, and while some dogs do okay that way it’s better to give a smaller dose daily. Again, mimicking what functional adrenal glands would do.

Most veterinary offices only carry 5mg tablets. I highly recommend getting a prescription for 1mg tablets, which can be filled at any human pharmacy. If your vet refuses to write or phone in a prescription for you, find a new vet.

Prednisolone is available from your veterinarian or a human pharmacy in liquid form. The liquid is much easier to dose at lower levels.

It’s a lot to process, so if you’re reading this because your dog has Addison’s and you’re feverishly trying to read everything you can about it then step one is to just stop and breathe. Fine-tuning the meds can come later, after you’ve adjusted to your new normal. Set down your tablet, or your phone, or turn off your computer and go give your dog a scratch. Hug them, but only if they like those. It’s going to be okay.

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