Cabergoline instead of pergolide

Eleanor Kellon, VMD

Cabergoline is a drug in the same class as pergolide but with much longer lasting effects in humans.  This is a thesis that looked at cabergoline (injectable)  vs pergolide (oral and injectable) in horses:

and additional information here:

This treatment is not quite ready for prime time and we still don't have any information on oral cabergoline but anyone with a PPID horse not responding well to pergolide could share this information with their veterinarian to discuss if it might be worth trying.

Also note this study confirms that oral pergolide only suppresses hormone levels for a few hours after you give it.

Eleanor in PA
EC Co-owner
Feb 2001

tara sullivan

Very very interesting.  My mare is responding to the pergolide as evidenced by her acth dropping, but she cannot shake the veil.  She is lethargic with an adequate enthusiasm for bucket meals but will eat her hay.  Makes me crazy that I have to syringe EVERYTHING....and it is interfering with our relationship....she is now very suspicious of me when I want to spend time with her.  I hold up my hands, like in a stick up! LOL!  to show her...I got nuthin!  It is scratch time. 
Question:  Does this study suggest that the pergolide  dose be cut in half and given 2x a day??
Thank you,
Tara and Divina
NY 2014

Suzanne Mansolilli

---Also note this study confirms that oral pergolide only suppresses hormone levels for a few hours after you give it.

If the above is true,  curious as to why  the dosage is recommended to be administered 1x/day instead of a split dose?


SuzanneM & Monty

Western Colorado — July 2014

Eleanor Kellon, VMD

This study, and others before it, suggest double dosing, not split dosing. The dose determined to be effective should be repeated at 12 hour intervals, if not sooner.

To see what YOUR horse needs, do timed testing. Test at 3-4 hours or less after dosing = peak effect. Test at 10+ hours = what happens the rest of the day.

To return to the 2mg example, on split dosing you would give 1 mg AM and PM. If you already know 1 mg didn't get good results, all you will get is poor results twice a day.

The reason double dosing hasn't been routinely suggested yet (besides the usual inertia) is that full details of the pharmacokinetics of pergolide are not know. We know levels drop significantly sooner than in people, and now know that ACTH follows a similar curve, but we don't know how quickly the horse eliminates the entire dose. Is it gone by 12 hours? 24 hours? Does it accumulate for a few days until steady state is reached? If it does, is it enough to even care?

If having trouble controlling your horse, double dosing is something to consider discussing with your vet. To start, do an ACTH 12+ hours after your last dose.

Eleanor in Pa

EC Co-owner

Feb 2001

lj friedman

Dr.kellon wrote this.

Also note this study confirms that oral pergolide only suppresses hormone levels for a few hours after you give it. 

Can someone explain what this vs  cabergoline means?    Just a few hours doesn't sound like pergolide isnt doing a job but I believe it does?Lj friedmAn san diego

Tina Martin

I read the study and am very interested in trying cabergoline to see if it does a better job controlling Rio's ACTH.  He has been on large dosages of compounded pergolide for years and his ACTH has never been controlled.  I have been giving 36mg pergolide in the morning and another 5mg at night for a few months now.  Just had his blood work done Tuesday but no results from my vet yet.  I dropped his dosage to only(!) 36mg in the AM after the blood was taken though because he is doing well now and I'm hoping the seasonal rise is over for him.

I'm unsure how to go about trying the cabergoline.  Can it be compounded?  If not it will also be very expensive (around $50 for 4 tablets of 0.5mg per online search).  The study administered 5mg in a slow-release vehicle (not sure what that means) intramuscular and it lasted up to 10 days.  How much should I give to Rio and how often?  And should I still give pergolide, and if yes at what dose?

Also, I don't mind the cost of frequent bloodwork but run into logistical problems since I now live in a rural area with my vet traveling around 40 miles to see me.

I would love to give this a try but would need some help since my vet isn't very familiar with this disease and treatment.

Dr. Kellon, please let me know if it is possible to have a private consultation with you regarding a possible trial of cabergoline.  Or please just let me know what your thoughts are.  Rio's ACTH may not be controlled but he seems to feel well and is sound enough to be ridden regularly for several hours on rough mountainous terrain. So maybe "leave well enough alone"? :)  


Tina & Rio
Georgia, May 2011
(there is a case history somewhere)

Lorna Cane

Tina Martin

Thanks, Lorna.

I updated Rio's case history.  Can you delete the old hay balancing file in my folder?  I cannot do it because I didn't add it.  Thanks again,

Tina & Rio
Georgia, May 2011


Lorna Cane

>  Can you delete the old hay balancing file in my folder? 

You're welcome,Tina.

File deleted.