Next steps adjusting pergolide: getting my vet on board


I wrote several weeks ago that Satra's ACTH tested on Oct. 19 at 12 pmol/L. Susan kindly converted pmol/L to pg/ml at 54.48 pg/ml.

Satra has been on 1 Prascend for about a month. She is apparently compensated IR (need to pick up test results). Satra is no longer footsore, the symptom that lead to the testing and diagnosis. She still has a long, silky coat (it's winter), and she is pot-bellied (former broodmare). She also drinks almost twice as much as my other mare and urinates accordingly. She has a strong appetite - not quite ravenous, but often acting hungry. That's the sum total of her symptoms.

When I asked my vet to do a follow-up ACTH test now that Satra has been on Prascend for a month, the response was that we should titrate dose based on clinical signs, as opposed to test results. Fair enough: I accept that I should administer pergolide if Satra still has symptoms with a normal ACTH result. But if Satra still has the most obvious PPID symptoms and her ACTH remains elevated, how can I know her dose is inadequate without testing? My vet seems to be under the impression that ACTH will never again be normal, even on pergolide. Is that correct? I garnered this from Files, don't know where:
"The effective dose is that dose which controls ACTH to below---
6.38 pmol/L (29 pg/ml) Nov - July
10.34 pmol/L (47 pg/ml) Aug to Oct."

Don't we need a follow-up ACTH test to know if the dose is adequate to control ACTH? Is hirsutism ever going to improve if ACTH is within the above ranges? The water consumption? The pot belly? The appetite?

In my vet's practice, minimal intervention is a common necessity, and I don't fault that approach. Thank goodness, I can do more than the minimum. I don't want to risk full blown laminitis for the lack of a blood test!

I want to provide my vet with research and references. Suggestions? An article published in a professional journal on titrating pergolide and reference ranges for controlled ACTH would be a start.


Cass for Satra
Sonoma County, Calif
Oct 2012

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