How to get Pergolide prescribed w/o or low ACTH results


I would like to know if anyone has had success to get pergolide / prascend prescribed without a positive ACTH test ?
I had 3 negative tests for an ols loan pony even though all the symproms were there : curly coat, fat pads, bulge above the eye. It is only when he has a full blown seizure in the arms of the vet that they agreed to prescrive Prascend. He is know a different pony : trim, shiny coat, no seizure.

I can see the same symproms appearing in my riding horse (Spanish and much younger)
- thick coat in sweltering summer, he was sweating all the time
- bulge above the eye starting to fill
- less keen to work, could be sore in hs feet, yet starting to shy more / looking worried

I am pretty sure that the process has started with him and willing to bet that the test will be also negative. Can I ask the vets to put on Prascend any way and look for improvements (as we did with the pony) ? what are the downsides ? how to convince them ?

Nathalie, UK
Carer of Timmy and owner of Palermo

Eleanor Kellon, VMD

You should have the exact same conversation with your vet. I would test at least once though. It will give you a baseline for evaluating dosage.
Eleanor in PA 
EC Owner 2001
The first step to wisdom is "I don't know."

Sherry Morse

Fat pads and bulges over the eyes are symptoms of IR not PPID.  You need to test for both conditions in both animals - insulin, glucose and ACTH.  If possible (not sure what's available in the UK) you should use the TRH Stim test to see what the results are post stim if the ACTH is normal at baseline. 

Looking at your old test results Palermo is IR and had an elevated ACTH in 2019.  The same results are evident for Roxy.

Updating your Case Histories with more recent test results would be very helpful as well as updating diet information and body condition as both were overweight when you first completed those case histories.

Can we also ask you to please add the year you joined the group to your signature?  This is helpful for us to know how long you've been with ECIR and how familiar you are with are protocols.

Lesley Fraser

Hi Nathalie

Omar's vet was initially disinclined to carry out any ACTH/IR testing, insisted it wasn’t necessary and told me I’d be wasting my money. I asked them if they'd humour me and do it anyway, which they did, and Omar's ACTH and IR results turned out to be high. The vet was very surprised and apologised for having tried to put me off.

If your vet doesn’t normally use this lab, I’d suggest asking them use the Liphook Equine Hospital Laboratory (they offer the TRH Stim test that Sherry mentioned) for the bloods. I used them for Omar’s bloods over several years, and their service was accurate, reliable and speedy. You probably already know this, but make sure you follow the testing guidelines on ECIR about timing/feeding beforehand.

Also, ask the vet for a copy of the actual lab results, which the surgery can email to you, and post them in your Case History.

Lesley and over the bridge Omar,
11-2012, Sutherland, UK

Omar - Case History


Just to make sure, I got this right... Even though my current practice (not the one that analysed the case histories) always read low ACTH values even with an advanced text book PPID horse, you think that the TRH test will work because it relies on 2 values. So even if they generally read low, a higher 2nd value should confirm the PPID diagnosis regardless of the value?
Liphook also recommend not testing before mid Nov, so should I wait or just rely on seeing a difference between the 2 ACTH values ?
I have been searching under files and Wiki for reference documents regarding these tests (I have read them in the past) but right now, I cannot locate them. Would you mind pointing me in the right direction ?

Sherry, I don't understand why you say that fat pads and filled eyes are not related to PPID. I quote from Liphook all the symptoms that the pony displayed:

Generalized hypertrichosis, Skeletal muscle atrophy, Rounded abdomen (‘hay belly’), Bulging supraorbital fat, Laminitis, Seizure-like activity, Loss of epaxial muscle mass (topline), Regional adiposity

Nathalie, UK, 2019
Roxy over the rainbow and owner of Palermo

Sherry Morse

Hi Nathalie,

I'm a bit confused as both of your horses had elevated ACTH in 2019.  I'm not sure how any vet could have read that as low - can you please elaborate on that?  

If you have a horse that presents with low ACTH at baseline but you think is PPID that's when you would test with the TRH Stimulation test to see if they have an elevated number at the 10 minute mark. If they do that's an indication that they are in fact PPID (or early PPID) in spite of the low initial number.   

The recommendation is not do a TRH Stim until after the rise, and officially that would be January. If you are testing horses that are already on Prascend or Pergolide be aware that there is no established post-TRH range but we would expect them to be in a lower range if they are controlled by medication. That's one of the studies Drs. Kellon and Gustafson have undertaken this year.

I've asked Dr. Kellon about the symptoms that you quoted from Liphook (and which they list as advanced PPID) as I still believe they are mixing the 2 conditions.