Side effects of large doses of Florinef

Started by patp, October 23, 2013, 06:57:41 PM

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My Whippet, Willow, has not been balanced with her Addisons for some time. She struggled to keep her Sodium levels up on the normal doses of Florinef. The first opinion practice, with my encouragement, increased her Florinef gradually until her Sodium levels reached an acceptable level. She was on 4 Florinef twice daily in order to maintain this. After several changes of vets within this practice I had to consult the referral practice that knew Willow's case in order to have some sort of continuity. The referral practice were of the opinion that Willow was on far too high a dose of Florinef and have been overseeing a gradual reduction in the dosage.
All through this process Willow has been drinking excessively and peeing accordingly. This has meant that we usually come down in the morning to a flooded area of the bathroom where she now has to sleep. She has ruined two carpets when she was not able to make us understand that she needed to go out. If we go out she has to be confined to the bathroom with newspaper to wee on.
My question is about the drinking and peeing. The vets have said that she is concentrating her urine, though the last test was not so good. Is this a result of the high levels of Florinef? If so will it improve? Have the drugs damaged her kidneys?
Before using the high dosages of Florinef Willow had been on Prednisolone. This had a really bad effect on her and it was this effect that caused her to be referred, originally, to the specialist practice.



Dogs on too much Florinef may suffer from  mild Cushing's syndrome as a result of too much glucocorticoid replacement within the Florinef tablet.

The symptoms will be:  drinking and weeing too much.  Wanting to eat more and weight gain. When a dog is Cushingoid they are unable to fully concentrate the urine.  If the Florinef is too high, when you reduce it the clinical signs will disappear and she will return to normal.  No damage would have been done to the kidneys.  There is only a small proportion of 'pred' in Florinef.  The replacement dose of pred when used in stressful situations is 0.2mg/kg/24hrs.  This is a replacement dose because the body is no longer able to produce it in stressful situations.

The object is to give enough replacement hormone to bring the sodium and potassium back to within normal limits and the resolution of clinical signs of Addison's disease.  This is usually achieved on Florinef alone and using pred at times of stress.  A 'replacement' dose is the aim and not an excess of hormones.  Perhaps enough time, in the early days of diagnosis, wasn't allowed for the body to adjust to the replacement hormones.  It can take a while for the body to stabilise.  4 Florinef twice a day does seem pretty high for a whippet.   

Sodium and potassium should be considered as a whole picture (not just one or the other)  and the ratio should reflect the clinical signs.

I hope you see an improvement when the dose is reduced.



Thank you Jo for such a clear explanation.
Well the drinking and weeing part of Cushings certainly fits but not the eating and weight gain. She is on the thin side, even for a Whippet, and is a nightmare to feed. She only ever eats one or two meals of any dog food before going off it. The longest she has ate any food is when it is mixed with NaturesMenu. She eventually even went off that.
Willow has had two days without weeing overnight. This has happened before so I am not getting too excited though it felt like a holiday not to have to wash floors!
I rang the vet to report the increase in, what I thought was already excessive, drinking. The vet asked us to measure how much Willow was drinking. Day one - 1ltr, Day two - 1.2ltr, Day three - 1ltr and now Day four - 500ml. Is this truly excessive would you think? It seems it to me. She is down to 2 Florinef twice daily now and has been for about three weeks. We have, however, found a dry food (Fish4Dogs) that she is eating fairly well and so I thought that might be part of the reason for her drinking more. She would, normally, have wet food mixed in to get her to eat it.

Willow also seems grumpy. She does not tolerate other dogs in her space. She is also quite suspicious of strangers and jumpy around lively children. I just wonder, sometimes, if she is enjoying life...

Penel CIMDA moderator

(SLE, Surrey - UK)
Forum Owner



I asked Willow's vet (a referral practice) about the Thyroid test. She said it had been checked before (true) and it was normal so no point doing it again. She is firmly of the opinion that the symptoms are due to an excess of Florinef.
She does say that the drinking is rather excessive for a dog of Willow's size. Her opinion is that it is caused by the large dose of Florinef she has been on. The dose of Florinef when the latest lytes were tested was 2 tablets twice daily.

The latest lytes are:_

31st October

Sod    135    range 139-154
Pot     4.4               3.4-5.6
Chlor  102              105-122

She is not concentrating her urine very well either.

As the sodium has dropped out of the normal range I have been told to increase the Florinef to the previous dose of 2.5 tablets twice daily. She then has to go for a lytes check in four weeks.

The vet thinks that Willow is lethargic because she has "grown up" and she is cold because Whippets feel the cold. She says she has no other signs of Thyroid deficiency.



Has she had a thyroid test since the one you posted about in May last year? If not and as the T4 was low then, perhaps another test does need to be done and including a FreeT4 as well.

Perhaps the low sodium and not concentrating urine very well is due to the increased intake of water.

I would have thought a young dog should not be lethargic even if it is no longer a puppy and lethargy can certainly be a sign of Hypothyroidism but can also be caused by other problems.


Hi Catherine
Can you point me in the direction of those Thyroid results please? Did I post the actual results of just say they were low?

Someone else has mentioned Thyroid in Willow's case but I can't remember when she was last tested and what they were. I can't get the referral vet to test her. I have already gone over her head once and we don't have a good relationship now.

I think Willow had a thyroid test when she went back to referral but I don't know the numbers. The vet just says the results were normal.



Pat, they are under the thread you started : Implications of delayed diagonis of Addisons?  I have not read all the posts but here is a copy of the bit I saw about the thyroid results:

Endocrine diseases (hypothyroidism, Addison's) / Re: Implications of delayed diagonis of Addisons?
« on: May 30, 2012, 10:20:57 AM »
Thanks Jo
Willow weighs 10.7 kg at the moment but is usually around 11.5kg.

The latest lytes I have are from the 22nd
Na 138   Reference range 136 - 156
K    4.6    Reference range 3.4 - 5.4
Cl   121         "            "      96 - 122 (what is Cl please?)

The Bile Acid Stim Test came back normal according to the vet

The thyroid test is:-

Canine Total T4  5.11  normal range 10.00 - 50.00
Canine TSH         0.06       "        "      0.05 - 0.60

The vet tells me that dogs that are poorly often have low thyroid results and she is not too worried. She said she will do another test in a couple of weeks.

I am awaiting my copy of the full blood screen done the day before yesterday. The vet was happy with the lytes but said the red blood cells were low and white cells were up which were indicative of an infection (she had vomited and passed very loose stools that morning).

I checked that the dosage Willow is having was correct with both the Florinef and the Prednicare.

Willow is well in herself. Hungry but fussy what she eats. Not overly thirsty. As I am usually up in the night I let her out for a wee and she always wants to go. The only not normal thing at the moment is very smelly wind and quite a lot of it. Considering she is on Stormagyl for her V&D I wondered if that would cause the wind?

Is the referral vet your normal local one? If not your usual vet could do the test.


Thanks Catherine
I was thinking the same as you! I will try with the referral vet for the sake of continuity but be prepared to go to my first opinion vet if necessary.


I now have the latest test results from my vet. I have copied them below.

I asked the vet to let me have the last Thyroid test results at the same time. As you can see they were taken in February.

  31/10/2013    BIOCHEMISTRY

Sample quality             Clear.

Urea                     * 7.9        mmol/l    High (2.5 - 7.4)

Creatinine                 98         umol/l         (40 - 145)

Potassium                  4.4        mmol/l         (3.4 - 5.6)

Sodium                   * 135        mmol/l    Low  (139 - 154)

Sodium:potassium ratio     30.7                      (>27.0)

Chloride                 * 102        mmol/l    Low  (105 - 122)





T4                         17.5       nmol/l         (13.5 - 50)

TSH Canine                 0.10       ng/ml          (0.0 - 0.60)

Free T4                    15.0       pmol/l         (7.0  - 40.0 )

Overnight I have been thinking about the symptoms of thyroid deficiency. Willow, we know already, is lethargic and feels the cold. She has also been lame for some time. X-rays failed to find anything and she now has regular acupuncture. It is seated in the left hip area as the physio was able to find some tense muscles which she released but it has never resolved the cause of the lameness. Willow continues to hop occasionally.
I was trying to make my vet understand how unhappy Willow seems and I described her as "laying on the sofa, with her eyes open, looking pathetic". I now see that hypo thyroid dogs have a "tragic" expression.

Not sure if the above results tell us anything?



Just realised that Wilow was on Prednisolone when that Thyroid test was taken in February. She was on 2.5mg every other day. The last tablet was given on 26th February. Not sure if that would have affected the results?


Yes it could. Also is Willow spayed? If she is entire still that can affect the results if the test is done at certain times of her hormone cycle.

Penel CIMDA moderator

And one big thing we've all been missing is that sighthounds have a different range to 'normal' dogs.

I exchanged emails with Jean Dodds earlier this year about a behaviour case I was consulting on - and below is part of her email - re the ranges for a whippet are in italics.

T4 Normal range 7 – 35   should be at least 9 nmol/L for a sight hound

FreeT4 Normal range 6.6-40  - should be at least 14 pmol/L

TSH Normal range 0.01-0.6  – should be less than 0. 30
(SLE, Surrey - UK)
Forum Owner


Willow is spayed. Another story there! She was poorly and had just finished her season. She was admitted for tests etc and they could not get to the bottom of what was wrong with her so they decided it might be a pyo. She was consequently spayed. Perhaps her symptoms then were more to do with thyroid issues?

Interesting point about sighthounds. Does that make Willow's results better or worse?

I have seen, elsewhere, some information on Schmidt's Syndrome (autoimmune polyendocrine disorder }and I am going to get in contact with my vet to see if I can persuade her to follow it up with a thyroid test.