FDA Licensing Field Trial Proves
PRASCEND® (pergolide mesylate) Efficacy1,2

In a large, multi-site field efficacy study approved by the FDA, PRASCEND was effective in controlling clinical signs associated with PPID in horses and ponies.

Efficacy study parameters

One hundred thirteen male and female horses and ponies representing 16 different breeds in locations throughout the US were evaluated in the field trial. The horses were either privately or university-owned. Horses were aged 10 to 35 years and weighed 302 lb to 1,370 lb. All the study horses had been diagnosed with PPID prior to starting treatment with PRASCEND.

All horses received pergolide once daily for 180 days. Because of the progressive, life-threatening nature of unmanaged PPID, an untreated control group was not included in this study.

Dosage administration1,2

Horses were given PRASCEND tablets containing 1.0 mg of pergolide mesylate in each tablet. The target starting dose for each animal was 2 mcg of PRASCEND per kg of body weight. If endocrine test results remained abnormal at study Day 90, the target dose was increased to 4 mcg/kg.

The target oral regimen of 2 to 4 mcg/kg given once daily was selected for use in the PRASCEND clinical trial based on a review of responses to various doses of pergolide reported in the scientific literature in past years. Most recent reports have used an oral daily dose of approximately 2 mcg/kg.3,4

For complete PRASCEND dosage and administration information, click here.

Efficacy study results1,2

Investigators determined that 76% (86 of 113 horses) were treatment successes based on endocrinologic testing results and/or clinical scores. As seen in Table 1, horses showed improvement in clinical signs within 3 months and further benefits of treatment after 6 months. Hirsutism, the shaggy hair coat considered to be a key indicator of PPID, improved in an impressive 89% of treated horses.

Each of the treatment successes (n=86) showed the following results within 180 days:

  • ACTH test results returned to normal or decreased by at least 50%
  • DST returned to normal (<1 mcg cortisol per dL) on Day 180
  • Improvement in at least one clinical sign
  • No worsening in any clinical signs or development of new signs

All clinical signs evaluated showed improvement within 3 months and continued results after 6 months

Clinical signs Percent of horses showing improvement
90 days 180 days
Hirsutism 33% 89%
Hyperhidrosis 27% 42%
Polyuria/polydipsia 31% 34%
Fat distribution 21% 33%
Muscle wasting 36% 46%

Total clinical scores were reduced by nearly 70%

*Two horses were withdrawn from the study prior to Day 180.

Summary of the most common adverse reactions (N=122)
Clinical signs # Cases Cases (%)
Decreased appetite 40 32.8
Lameness 22 18
Diarrehea/loose stool 12 9.8
Colic 12 9.8
Lethargy 12 9.8
Abnormal weight loss 11 9.0
Laminitis* 10 8.2
Heart murmur 10 8.2
Death 8 6.6
Tooth disorder 8 6.6
Skin abscess 7 5.7
Musculoskeletal pain 6 4.9
Behavior change 6 4.9
*Three new cases and 7 pre-existing, recurring cases

Benefits you can see

Click here to see photos showing the improvement in hair coat and body condition score before and after PRASCEND treatment.

Important safety information

PRASCEND is for use in horses only. Treatment with PRASCEND has been observed to cause inappetance, with most cases being transient. Weight loss, lethargy, and behavioral changes may be observed in some horses. If severe, a temporary reduction of dose may be necessary. PRASCEND has not been evaluated in breeding, pregnant, or lactating animals. As PRASCEND is a dopamine agonist, it may interfere with reproductive hormones involved in these groups of animals. The concurrent use of dopamine antagonists should be avoided since these agents may diminish the effectiveness of PRASCEND. PRASCEND should not be used in horses with hypersensitivity to pergolide mesylate or other ergot derivatives. Refer to the package insert for complete product information.


  1. PRASCEND® (pergolide mesylate) [package insert]. St. Joseph, MO: Boehringer Ingelheim Vetmedica, Inc.; 2011.
  2. PRASCEND® (pergolide mesylate) [Freedom of Information Summary]. St. Joseph, MO: Boehringer Ingelheim Vetmedica, Inc.; 2011.
  3. Schott HC. Pituitary pars intermedia dysfunction: equine Cushing's disease. Vet Clin North Am Equine Pract. 2002;18(2):237-270.
  4. Donaldson MT, LaMonte BH, Morresey P, Smith G, Beech J. Treatment with pergolide or cyproheptadine of pituitary pars intermedia dysfunction (equine Cushing's disease). J Vet Intern Med. 2002;16(6):742-746.