Pergolide for HORSES – What we REALLY Know!

Uses and General Information on Pergolide for Equines

Pergolide for horses is a medication used to treat a disease that older horses can develop called Pars Pituitary Intermedia Dysfunction (PPID), also commonly known as equine Cushing’s. 

Despite the name equine Cushing’s, PPID is a very different condition to the Cushing’s disease you might know about in dogs. 

PPID is caused by a benign growth on the pituitary gland in a horse’s brain. This growth causes a deficiency in the hormone dopamine, which controls the production of some hormones. Without dopamine, a horse’s hormone levels become uncontrolled and can lead to a whole host of issues, including laminitis, delayed shedding of hair, and changes in attitude.

Unfortunately, PPID cannot be cured, but the good news is that it can be managed using a medication called Pergolide, also known by its brand name Prascend.

Medication Pergolide

How to Give Your Horse Pergolide

Pergolide comes as a tablet that is administered orally, typically once a day.

You may be given the generic Pergolide for horses or the brand name product called Prascend. Both medications will have the active ingredient Pergolide in them. If you are unsure about what drug you have gotten, make sure to ask your vet.

Tablets are not the easiest thing to give to horses. Most veterinarians will recommend placing the tablet in a small amount of water and/or mixing it with molasses or other equine-safe sweetener and stirring it until the tablet has dissolved. The dissolved tablet can then be administered with a syringe into your horse’s mouth. 


The whole amount should be given immediately. Pergolide tablets should not be crushed.

To successfully treat PPID, your horse will need to have the medicine administered every day, so it is important to commit fully to the treatment course. Do not skip days or stop giving the medication without discussing it first with your veterinarian.

Suppose you are finding the administration difficult make sure to ask for advice. In that case, your veterinarian may be able to have the drug formulated by a pharmacy into a liquid for easier dosing.

If you miss a dose, give it as soon as you realize, but if this is going to be just a few hours from the next scheduled dose, it is best to wait and give the next amount at its regular time.

Horses are typically given a dose between 0.25mg to 3mg per day. Your horse will need to be on this medication for life as the benign growth on the pituitary gland will not go away.

To facilitate training horses to take Pergolide tablets, it may be helpful to start with just syringing a dilute molasses mixture for a few days to get them used to the process. Once they are comfortable taking the molasses by syringe, then the pergolide can be added. You may need to skip this step if your horse needs the medication urgently. Chat to your veterinarian for advice.

Precautions and Side Effects of Equine Pergolide

As with any medication, it is best to give the lowest effective dose. This will help limit side effects. Your veterinarian will prescribe an amount appropriate for your horse. This will vary from horse to horse. 

It is possible that as time goes on, your horse may become resistant to Pergolide. If you begin to see the signs of PPID return in your horse, let your veterinarian know that the dose may need to be increased to control the disease.

There is no known evidence that Pergolide is safe for use in lactating mares or breeding stallions. Therefore, Pergolide should only be used in pregnant or lactating mares if the benefits outweigh the risk. Make sure to discuss breeding your horse with your veterinarian if your horse is on Pergolide.

Certain governing establishments consider Pergolide a controlled medication, so make sure to check with your veterinarian before giving Pergolide to your competition horse.

Side effects that you may notice in your horse include a reduced appetite; this is the most common side effect and should go away in the first week. However, if the inappetence becomes severe, a reduced dose may be given for a few days. Chat to your veterinarian before changing the amount.

Stomach and intestinal upset can also occur. If you notice signs of colic, contact your veterinarian immediately. Pergolide can also cause an increased or irregular heartbeat, behavioral changes, and muscle twitching. 

female vet eaxmining horse

Drug Interactions and Pergolide Overdose in Horses

Phenothiazine tranquilizers such as Acepromazine may interfere with the action of Pergolide.

Other drugs can interact with Pergolide, so make sure to let your veterinarian know if your horse is on any other medications or supplements. 

Once your horse is on Pergolide, check with your veterinarian before changing your horse’s food or giving other medications or supplements.

Overdose in humans causes gastrointestinal upset and hallucinations. If you notice any colicking (gut pain) or behavioral changes in your horse, let your veterinarian know immediately.

Pergolide Storage Instructions

Make sure to keep your horse’s medication out of sight and reach of children. Store the Pergolide below 77°F. It is for animal treatment only and should not be consumed by people. Do not administer pergolide to other horses even if you think they have PPID. Each dose is tailored to a specific horse and should not be shared.

Any unused Pergolide should be disposed of safely. Veterinary clinics will often take back unused medication and dispose of it with their medical waste.

The Characteristics of Pergolide Use in Horses

Pergolide works by blocking the dopamine receptors in the hypothalamus (a part of the brain). This decreases the excessive production of some hormones and other mediators which cause the signs of PPID.

Pergolide has been approved by the FDA for use in horses with PPID through the brand name Prascend. There is much that remains unknown about how Pergolide works, but through studies, there are some key insights which have been found:

  • Pergolide takes effect quickly and helps to suppress hormone production within just a few hours of oral administration.
  • Pergolide does not accumulate in the horse’s body, and the levels stabilize quickly, usually within three days.
  • Pergolide is cleared quickly. Half of it will be gone from the body of horses within 12 hours.
  • Twice daily administration may be more beneficial for some horses. However, this is off-label (i.e., not approved by the FDA), so this is something you would need to discuss with your veterinarian first before trying.
vets and horse

FAQs on Pergolide for Horses

Below we have answered some commonly asked questions on Pergolide administration to horses:

My horse has been prescribed 1mg Prascend per day. Do I give him the full 1mg on the first day?

In general, no. It has been found that Prascend should be introduced slowly by giving partial doses over the first four days or by issuing half the quantity in the morning and evening. Then, the dose can be gradually increased to the full 1mg once daily. Discuss dosing with your veterinarian.

What is the Pergolide Veil, and how can I avoid it?

The “Pergolide Veil” is a phrase given to the side effects commonly seen with the administration of Pergolide/Prascend. Inappetence and depression are the most common side effects seen by the administration of Pergolide.  

To avoid the “Pergolide Veil,” the drug can be introduced slowly so that your horse can develop a tolerance to it. This may not always be appropriate; however, chat to your veterinarian before changing the dose. If you notice your horse becoming inappetant or depressed, your veterinarian can give you advice.

Some herbal supplements such as Advanced Protection Formula (APF) may help reduce the incidence of these side effects; chat to your veterinarian to see if these are appropriate for your horse.

Is there a particular time of day I should give the Pergolide/Prascend?

No. There is currently no recommendation for the time of day to give Pergolide/Prascend. It is typically given once daily.

Pergolide vs Prascend for Equines

As you may have noticed through reading this article, the words Pergolide and Prascend come up often. So what is the difference, you might be thinking? Well, Pergolide is the name of the drug. It is the active ingredient (technically called Pergolide Mesylate). 

It is what works to treat PPID in horses. Prascend is the brand name, and it is the only licensed drug available to treat horses for PPID. It is made by a company called Boehringer Ingelheim.

PPID is a condition of older horses that can cause severe problems if it is left untreated. The good news is that there is an effective treatment on the market, and it has been approved for use by the FDA. If your horse is prescribed Pergolide/Prascend, make sure to have a good understanding of the drug and chat to your veterinarian if you have any concerns.