pergolide dosing question


First post here so TIA for patience. I have a question about my horse's ACTH level in response to the prascend. His ACTH has come down quite a bit but is still above the normal range. My thought was to continue his current dose and recheck ACTH in another 3 months. But should I be more concerned about his high ACTH causing health complications? I want to balance his quality of life and side effects of the medication with controlling the PPID.

First ever bloodwork based on very mild signs suggestive of PPID: ACTH 9/25/22 was 540 pg/ml, range fall months <50 negative, 50-100 equivocol, >100 positive.
Prascend (pergolide) 0.5 mg/day started 10/18/22. Mild lethargy, and weakness when standing for hoof trims, but also not riding much so could be more significant lethargy just not noticed as much.
ACTH 12/18/22 was 153 pg/ml, range non-fall months <30 neg, 30-50 equiv, >50 pos. 

December 2022, Omaha, Nebraska
Rigel Case History:


Hi Mary,

Welcome to the ECIR group!  With your first post here we send a formal welcome with all sorts of information on metabolic laminitis, PPID and managing horses with those conditions.

Relatively recent data suggests that starting or increasing pergolide during the fall rise (Jul-Dec) is not as effective as other times.  With that in mind, I would wait until mid January to do any further testing to give the pergolide you’ve been giving a chance to catch up.  However, as we are no longer in the rise for most horses (some PPID horses have an extended rise), you should be fine increasing the dose now.

My horse, Logo, was relatively young when I started him on pergolide.  He was having unmanageable skin issues as well as ulcer like problems, both of which resolved after starting pergolide.  It never occurred to me that he might be PPID.  Things you might not have realized are related to PPID suddenly become much more manageable.  Having high ACTH is definitely not good for their health but the hair coat signs one usually relates to PPID don’t often appear until the disease has progressed.  If your horse is IR, which can be tested measuring insulin, according to our protocols, it’s even more important to control ACTH as it can exacerbate high insulin levels.  You haven’t tested insulin but, as your horse is a genetically prone to IR Arabian, I would recommend testing insulin and glucose the next time you test ACTH.

The side effects that come with pergolide often include lethargy but generally last just a few days.  We refer to this as the pergolide “veil”.  It can be mitigated by giving an adaptogen such as APF (Advanced Protection Formula) for several days before starting pergolide and continuing until you’ve reached what is suggested to be your dose goal, frequently 1 mg to get started.  If you feel that these side effects are still an issue, you could give APF now and see if it helps or discontinue pergolide, wait until the untoward effects disappear and then restart pergolide with APF on board.  The time to do that would be soon, before the next rise has a chance to build again.  What you seem to be noticing is not really a ‘side effect’ but the horse adapting to a new, more healthy, normal.  If you’re not really sure of what you’re seeing, I would increase the dose (pretreating dose of with APF) to 1 mg and take note of what happens over the next few days.  It’s important to sort out the dose before June when the next rise begins and that often takes more time than expected, although your being a vet will help facilitate that.


Now for all the details I promised.  Keep this information handy as it will continue to be useful.

Welcome to the group! 

The ECIR Group provides the best, most up to date information on Cushing's (PPID) and Equine Metabolic Syndrome (EMS)/Insulin Resistance (IR). Please explore our website where you'll find tons of great information that will help you to quickly understand the main things you need to know to start helping your horse. Also open any of the links below (in blue font) for more information/instructions that will save you time.

Have you started your Case History? If you haven't done so yet, please join our case history sub-group. We appreciate you following the uploading instructions so your folder is properly set up with the documents inside. Go to this CH message with info on how to use various devices and forms. If you have any trouble, just post a message to let us know where you are stuck. 

Orienting information, such as how the different ECIR sections relate to each other, message etiquettewhat goes where and many how-to pages are in the Wiki. There is also an FAQs on our website that will help answer the most common and important questions new members have. 

Below is a general summary of our DDT/E philosophy which is short for Diagnosis, Diet, Trim and Exercise.


DIAGNOSIS: There are two conditions dealt with here: Cushings (PPID) and Equine Metabolic Syndrome (EMS)/Insulin Resistance (IR). These are two separate issues that share some overlapping symptoms. An equine may be either PPID or EMS/IR, neither or both. While increasing age is the greatest risk factor for developing PPID, IR can appear at any age and may have a genetic component. Blood work is used for diagnosis as well as monitoring the level of control of each.

PPID is diagnosed using the Endogenous ACTH test, while EMS/IR is diagnosed by testing non-fasting insulin and glucose.

The fat-derived hormone leptin is also usually abnormally elevated in insulin resistance but because there are many other things which can lower or increase leptin ECIR is not recommending routine testing for this hormone. Leptin is the hormone that says "stop eating".

In Europe, adiponectin is tested instead of leptin. Adiponectin helps regulate glucose and fat burning, and maintain insulin sensitivity. Low levels are associated with EMS. It has come to be preferred over leptin because it is not influenced by things like weight or exercise, and also because it was the only factor other than insulin levels that predicted laminitis risk

*Before calling your vet to draw blood for tests, we suggest saving time and wasted money by reading these details and then sharing them with your vet so that everyone is on the same page regarding correct testing and protocols.

*Please remember to request copies of the results of all the tests done rather than just relying on verbal information. Your vet should be able to email these to you. If you have previous test results, please include those as well. All should go in your CH, but if you are having any trouble with the CH, just post in the messages for now. 

Treatment: EMS is a metabolic type - not a disease - that is managed with a low sugar+starch diet and exercise (as able). The super-efficient easy keeper type breeds such as minis, ponies, Morgans, Arabs, Rockies are some of the classic examples. PPID is a progressive disease that is treated with the medication pergolide. Some, but not all, individuals may experience a temporary loss of appetite, lethargy and/or depression when first starting the medication. To avoid this "pergolide veil" (scroll down for side effects), we recommend weaning onto the drug slowly and the use of the product APF. The best long term results are seen when the ACTH is maintained in the middle of the normal range at all times, including during the annual seasonal rise. To accomplish this, the amount of medication may need to increase over time. Neither condition is ever "cured", only properly controlled for the remainder of the equine's life. If your partner is both PPID and IR then both medication and diet management will be needed. 

DIET: Almost all commercial feeds are not suitable - no matter what it says on the bag. Please see the International Safe Feeds List for the safest suggestions.

No hay is "safe" until proven so by chemical analysis. The diet that works for IR is:

  • low carb (less than 10% sugar+starch)
  • low fat (4% or less) 
  • mineral balanced  

We use grass hay, tested to be under 10% ESC + starch, with minerals added to balance the excesses and deficiencies in the hay, plus salt, and to replace the fragile ingredients that are lost when grass is cured into hay, we add ground flax seed and Vitamin E. This diet is crucial for an EMS/IR horse, but also supports the delicate immune system of a PPID horse. 

*Until you can get your hay tested and balanced we recommend that you soak your hay and use the emergency diet (scroll down for it).  The emergency diet is not intended for long term use, but addresses some of the most common major deficiencies. Testing your hay and getting the minerals balanced to its excesses and deficiencies is the best way to feed any equine (look under the Hay Balancing file if you want professional help balancing). If you absolutely cannot test your hay and balance the minerals to it, or would like to use a "stop gap" product until you get your hay balanced, here's a list of "acceptable" ration balancers

There is a lot of helpful information in the start here folder so it is important you read all the documents found there. The emergency diet involves soaking your untested hay for an hour in cold water or 30 minutes in hot water. This removes up to 30% of the sugar content, but no starch. Starch is worse than sugar since it converts 100% to glucose while sugar only converts 50%, so starch causes a bigger insulin spike. Make sure you dump the soaking water where the equine(s) can't get to it. 

What you don't feed on the EMS/IR diet is every bit as, if not more important than, what you do feed! No grass. No grain. No sugary treats, including apples and carrots. No brown/red salt blocks which contain iron (and sometimes molasses) which interferes with mineral balancing, so white salt blocks only. 

No products containing molasses. No bagged feeds with a combined sugar and starch of over 10% or starch over about 4%, or fat over about 4%. Unfortunately, even bagged feeds that say they are designed for IR and/or PPID equines are usually too high in sugar, starch and/or fat. It’s really important to know the actual analysis and not be fooled by a name that says it is suitable for EMS/IR individuals.

We do not recommend feeding alfalfa hay to EMS/IR equines as it makes many of them laminitic. Although it tends to be low in sugar, many times the starch is higher and does not soak out. Additionally, protein and calcium are quite high, which can contribute to sore footedness and make mineral balancing very difficult.

TRIM: A proper trim is toes backed and heels lowered so that the hoof capsule closely hugs and supports the internal structures of the foot. Though important for all equines, it's essential for IR and/or PPID equines to have a proper trim in place since they are at increased risk for laminitis. After any potential triggers are removed from the diet, and in PPID individuals, the ACTH is under control, the realigning trim is often the missing link in getting a laminitic equine comfortable. In general, laminitic hooves require more frequent trim adjustments to maintain the proper alignment so we recommend the use of padded boots rather than fixed appliances (i.e. shoes, clogs), at least during the initial phases of treatment.

Sometimes subclinical laminitis can be misdiagnosed as arthritis, navicular, or a host of other problems as the animal attempts to compensate for sore feet. 

You are encouraged to make an album and post hoof pictures and any radiographs you might have so we can to look to see if you have an optimal trim in place. Read this section of the wiki for how to get a hoof evaluation, what photos are needed, and how to get the best hoof shots and radiographs.

EXERCISEThe best IR buster there is, but only if the equine is comfortable and non-laminitic. An individual that has had laminitis needs 6-9 months of correct realigning trims before any serious exercise can begin. Once the equine is moving around comfortably at liberty, hand walking can begin in long straight lines with no tight turns. Do not force a laminitic individual to move, or allow its other companions to do so. It will begin to move once the pain begins to subside. Resting its fragile feet is needed for healing to take place so if the animal wants to lay down, do not encourage it to get up. Place feed and water where it can be reached easily without having to move any more than necessary. Be extremely careful about movement while using NSAIDs (bute, banamine, previcox, etc.) as it masks pain and encourages more movement than these fragile feet are actually able to withstand. Additionally, NSAIDs (and icing) do not work on metabolic laminitis and long term NSAID use interferes with healing. Therefore, we recommend tapering off NSAIDs after the first week or so of use. If after a week's time your equine's comfort level has not increased, then the cause of the laminitis has not been removed and keeping up the NSAIDs isn't the answer - you need to address the underlying cause.


There is lots more information in our files and archived messages and also on our website. It is a lot of information, so take some time to go over it and feel free to ask any questions. If you are feeling overwhelmed, don't worry, you will catch on, and we are always here to help you! Once you have your case history uploaded, we can help you help your equine partner even better.

For members outside North America, there are country specific folders in the files and many international lists in the wiki to help you find local resources.

If you have any technical difficulties, please let us know so we can help you. 

Martha in Vermont
ECIR Group Primary Response
July 2012 
Logo (dec. 7/20/19), Tobit(EC) and Pumpkin, Handy and Silver (EC/IR)

Martha and Logo

Sherry Morse

Hi Mary,

Welcome to the group! 

As we're past the seasonal rise and his ACTH is still quite elevated I would not wait to see how things go but plan on getting him up to at least 1mg now and retesting in 3 weeks after being on that dose.  I would pleasantly surprised if that's enough to get him to the upper teens/low 20s range we like to see PPID horses at year-round; but then you'll know if he needs to have another dose increase right away or not.  You definitely want to get his ACTH under control ASAP and if you have not had his insulin checked yet you'll want to add that in on the next round of testing just to make sure that's not a problem as well.

Given how out of control his ACTH was during the rise and the current level it wouldn't be out of line if he needed a dose of 2mg a day to get the ACTH down to a safe level so be prepared for that to happen.  If he's not IR as well as PPID you have more leeway with safe feeds which is why getting that checked is important.

As far as weakness while holding up his feet - PPID effects tendon and ligaments and that could well be related to the elevated ACTH or just general old age.  For our oldies we usually wrap them for the farrier to give some extra support and we'll give them bute too if needed to help.  If you have a good farrier they can probably trim by just getting the foot up on a block so it's elevated but the horse doesn't have to hold the leg up and balance on the other 3 legs.  

ACTH 12/18/22 was 153 pg/ml, range non-fall months <30 neg, 30-50 equiv, >50 pos. 


Thank you both! Yes Martha, I am a vet but have worked exclusively in small animal/companion exotic medicine for the past 17 years since I graduated and so I'm trying to catch up on current equine medicine since this has come up! I must say I have learned a lot in the past 3 months and learning every day. 

I do plan to check insulin next time I check ACTH, I did not think of that initially because he did not seem like EMS this fall and I was not current on my understanding of equine metabolic diseases. As for testing, I initially used Idexx because that's what my small animal clinic uses, but I was looking at Cornell and the prices are much better. What labs do most of you use? Besides ACTH, insulin, and glucose, what else should I consider testing when I draw blood again? Also, since he eats his grain/smart beet twice daily, and not a shred of hay, he's essentially fasted overnight - is it best to pull for the insulin/glucose prior to eating or afterwards or both? 

Finally, do most horses maintain on a steady dose year round? Is there any increasing/decreasing dose depending on time of year? 

As for hoof care, my father is retired but continues to trim my horses who live at his acreage. He (the horse) has always been barefoot for the 27 years he's lived there. He's extremely well behaved and patient with his feet. They are checked/filed every 4 weeks and trimmed when necessary. I have been learning to trim over the past 12 months and so it was definitely a noticeable difference the first trim after starting the prascend, which was about 1 month on it. We have been blessed that he has never been lame. I need to get a shorter hoof stand, my dad is 6'3" and his stand is tall, so far the horse has handled it fine but yes he is an oldie. 

Thank you again for the good information and I am glad to have found this group!
December 2022, Omaha, Nebraska
Rigel Case History:

Sherry Morse

Hi Mary,

We recommend Cornell for bloodwork and for our purposes you just need to check ACTH, insulin and glucose.  Information on how to do bloodwork can be found on the website at DDT +E – Diagnosis | ECIR Group, Inc. (  You will want to pull blood at least 4 hours after the first meal of the day so the insulin spike from eating after fasting has had a chance to dissipate.

Whether or not your horse will need a dosage increase for the seasonal rise is very individual.  This time of year is the best time to sort out a baseline dose and then you can check during the seasonal rise to see if that dose is enough during the rise or if you'll need a dosage increase just for it.

Eleanor Kellon, VMD

No worries. We wouldn't judge if your dad was barefoot for 27 years!

On fed/fasted, fasting will lower all the values. Pull at least 4 hours after the first meal of the day and try to go no longer than 4 hours with no food on test day. We mostly use Cornell.  ACTH, insulin and glucose is fine. Some horses maintain on same dose all year; others need increases for the fall seasonal rise. Some very early cases can decrease February through June but the cost of extra testing usually outweighs a medication savings and at his age I wouldn't try it.
Eleanor in PA  BOGO 2 for 1 Course Sale Through End of January
EC Owner 2001
The first step to wisdom is "I don't know."