FREE SHIPPING over $40
OVER 9000 FIVE-STAR REVIEWS
5% OFF ALL SUBSCRIPTIONS
100% HAPPINESS GUARANTEE
Analyze Diet
0
Home / Equine Research Bank / J Vet Intern Med / Long-Term Response of Equids With Pituitary Pars Intermedia ...
Journal of veterinary internal medicine2025; 39(3); e70109; doi: 10.1111/jvim.70109

Long-Term Response of Equids With Pituitary Pars Intermedia Dysfunction to Treatment With Pergolide.

Abstract: Limited data document long-term responses of equids with pituitary pars intermedia dysfunction (PPID) to pergolide treatment. Objective: Report clinical response, medical problems, outcome, and owner satisfaction with pergolide treatment of PPID-affected equids over 14 years. Methods: Thirty client-owned equids with PPID. Methods: After completion of an open field clinical efficacy study for Prascend® (pergolide tablets), 28 horses and two ponies were enrolled in an extended treatment study (13 receiving 2 μg/kg PO q24h and 17 receiving 4 μg/kg PO q24h). Clients were interviewed every 3 months and equids were re-evaluated after 2.5, 3, 3.5, 4.5, 5.5, 6.5, 9.5, 12.5, and 14.5 years of treatment. Results: Five equids died and 24 were euthanized (five for chronic laminitis) during the study period (median survival time, 3.6 years; range 0.6-10.5 years). Seven of 13 equids had a dosage increase to 4 μg/kg PO q24h (maximum study dose) between 1.7 to 4.7 years of the study. After 5.5 years, owners of 13 surviving equids reported sustained clinical improvement and endocrine test results normalized in 75%. After 9.5 years of treatment, only two of six surviving equids had normal endocrine test results. Conclusions: Long-term treatment of PPID-affected equids with pergolide produces clinical improvement in nearly all affected animals and normalization of endocrine test results in some cases. Furthermore, this extended treatment study determined that equids can respond favorably long-term to the initial pergolide dose, rather than needing a progressive increase in dose over time.
© 2025 The Author(s). Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.
Get Full Text
Publication Date: 2025-05-03 PubMed ID: 40317948PubMed Central: PMC12046498DOI: 10.1111/jvim.70109Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
LinkedInCopy
  • Journal Article
  • Clinical Trial
  • Veterinary

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research article studied the long-term effects of pergolide treatment on horses and ponies suffering from Pituitary Pars Intermedia Dysfunction (PPID), over a period of 14 years. It revealed that pergolide treatment led to clinical improvement in nearly all the animals and normalization of endocrine test results in some cases.

Research Objectives

  • The study aimed to document the long-term responses of equids (horses and ponies) with PPID to pergolide treatment.
  • It also planned to report on PPID-related clinical response, medical problems, overall outcomes and owner satisfaction with the treatment over a period of 14 years.

Methodology and Study Population

  • For the research, 30 client-owned equids diagnosed with PPID were selected.
  • Following an initial open-field clinical efficacy study of pergolide tablets (Prascend), 28 horses and 2 ponies were enlisted for long-term observation.
  • Thirteen were given 2 μg/kg of pergolide, while the remaining 17 received 4 μg/kg.
  • Throughout the study duration, owners were interviewed every 3 months and the health of the equids was reviewed at various points over the 14.5 years.

Results of the Study

  • During the study, five equids died and 24 were euthanized (with five euthanizations being due to chronic laminitis). The median survival time was 3.6 years, with a range of 0.6-10.5 years.
  • Seven out of 13 equids required a dosage increase to 4 μg/kg after 1.7 to 4.7 years.
  • After 5.5 years, owners of 13 surviving equids reported continued clinical improvement. Additionally, endocrine test results normalized in 75% of the cases.
  • However, after 9.5 years, only two of the six surviving equids had normal endocrine test results.

Conclusions

  • The study concluded that long-term treatment of PPID-affected equids with pergolide could lead to clinical improvement in almost all cases and normalization of endocrine test results in some instances.
  • The research also determined that these animals could adequately respond to an initial pergolide dosage over long-term, without needing a progressive increase in dosage.

Cite This Article

APA
Schott HC, Strachota JR, Marteniuk JV, Refsal KR. (2025). Long-Term Response of Equids With Pituitary Pars Intermedia Dysfunction to Treatment With Pergolide. J Vet Intern Med, 39(3), e70109. https://doi.org/10.1111/jvim.70109

Publication

Journal of veterinary internal medicine
ISSN: 1939-1676
NlmUniqueID: 8708660
Country: United States
Language: English
Volume: 39
Issue: 3
Pages: e70109

Researcher Affiliations

Schott, Harold C
  • Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, Michigan, USA.
Strachota, Julie R
  • Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, Michigan, USA.
Marteniuk, Judith V
  • Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, Michigan, USA.
Refsal, Kent R
  • Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, USA.

MeSH Terms

  • Animals
  • Pergolide / therapeutic use
  • Horses
  • Horse Diseases / drug therapy
  • Pituitary Gland, Intermediate / drug effects
  • Pituitary Diseases / drug therapy
  • Pituitary Diseases / veterinary
  • Male
  • Female
  • Treatment Outcome
  • Dopamine Agonists / therapeutic use

Grant Funding

  • Michigan State University College of Veterinary Medicine Endowed Research Funds

Conflict of Interest Statement

Dr. Schott has received research funding from and has been a consultant to Boehringer‐Ingelheim Animal Health USA. Dr. Schott has also received travel support from Boehringer‐Ingelheim Animal Health USA. The other authors declare no conflicts of interest.

References

This article includes 31 references
  1. nAnon. USDA/APHISn, Age‐Related Trends in Demographics of Equids in the United States, https://www.aphis.usda.gov/animal_health/nahms/equine/downloads/equine15/Equine15_is_TrendsAge.pdf.
  2. Ireland JL, Clegg PD, McGowan CM. A Cross‐Sectional Study of Geriatric Horses in the United Kingdom. Part 1: Demographics and Management Practices. Equine Veterinary Journal 43 (2011): 30–36.
    doi: 10.1111/j.2042-3306.2010.00145.xpubmed: 21143631google scholar: lookup
  3. McGowan TW, Pinchbeck GL, Phillips C, Perkins N, Hodgson DR, McGowan C. A Survey of Aged Horses in Queensland, Australia. Part 2: Clinical Signs and Owner Perceptions of Health and Welfare. Australian Veterinary Journal 88 (2010): 465–471.
    doi: 10.1111/j.1751-0813.2010.00638.xpubmed: 21091457google scholar: lookup
  4. Welsh CE, Duz M, Parkin TDH, Marshall JF. Prevalence, Survival Analysis and Multimorbidity of Chronic Diseases in the General Veterinarian‐Attended Horse Population of the UK. Preventive Veterinary Medicine 131 (2016): 137–145.
    doi: 10.1016/j.prevetmed.2016.07.011pubmed: 27544263google scholar: lookup
  5. McGowan TW, McGowan CM, Pinchbeck GL. Prevalence, Risk Factors and Clinical Signs Predictive for Equine Pituitary Pars Intermedia Dysfunction in Aged Horses. Equine Veterinary Journal 45 (2013): 74–79.
    doi: 10.1111/j.2042-3306.2012.00578.xpubmed: 22594955google scholar: lookup
  6. Ireland JL, McGowan CM, Clegg PD. A Survey of Health Care and Disease in Geriatric Horses Aged 30 Years or Older. Veterinary Journal 192 (2012): 57–64.
    doi: 10.1016/j.tvjl.2011.03.021pubmed: 21550271google scholar: lookup
  7. Carmalt JL, Waldner CL, Allen AL. Equine Pituitary Pars Intermedia Dysfunction: An International Survey of Veterinarians' Approach to Diagnosis, Management, and Estimated Prevalence. Canadian Veterinary Journal 81 (2017): 261–269.
    pmc: PMC5644449pubmed: 29081583
  8. Andrews FM, McFarlane D, Stokes AM. Freedom of Information Summary. Prascend Tablets, Pergolide Mesylate, for the Control of Clinical Signs Associated With Pituitary Pars Intermedia Dysfunction (Equine Cushing's Disease) in Horses. Original New Animal Drug Application, NADA 141–331. .
  9. Schott HC. Pituitary Pars Intermedia Dysfunction: Equine Cushing's Disease. Veterinary Clinics of North America. Equine Practice 18 (2002): 237–270.
    doi: 10.1016/s0749-0739(02)00018-4pubmed: 15635907google scholar: lookup
  10. McFarlane D. Equine Pituitary Pars Intermedia Dysfunction. Veterinary Clinics of North America: Equine Practice 27 (2011): 93–113.
    doi: 10.1016/j.cveq.2010.12.007pubmed: 21392656google scholar: lookup
  11. Durham AE, McGowan CM, Fey K. Pituitary Pars Intermedia Dysfunction: Diagnosis and Treatment. Equine Veterinary Education 26 (2014): 216–223.
    doi: 10.1111/eve.12160google scholar: lookup
  12. Messer NT, Johnson PJ, Refsal KR, Nachreiner RF, Ganjam VK, Krause GF. Effect of Food Deprivation on Baseline Iodothyronine and Cortisol Concentrations in Healthy, Adult Horses. American Journal of Veterinary Research 56 (1995): 116–121.
    pubmed: 7695139
  13. Hurcombe SDA, Toribio RE, Slovis N. Blood Arginine Vasopressin, Adrenocorticotropin Hormone, and Cortisol Concentrations at Admission in Septic and Critically Ill Foals and Their Association With Survival. Journal of Veterinary Internal Medicine 22 (2008): 639–647.
    doi: 10.1111/j.1939-1676.2008.0090.xpubmed: 18466247google scholar: lookup
  14. Funk RA, Stewart AJ, Wooldridge AA. Seasonal Changes in Plasma Adrenocorticotropic Hormone and α‐Melanocyte‐Stimulating Hormone in Response to Thyrotropin‐Releasing Hormone in Normal, Aged Horses. Journal of Veterinary Internal Medicine 25 (2011): 579–585.
    doi: 10.1111/j.1939-1676.2011.0712.xpubmed: 21457320google scholar: lookup
  15. Storer WA, Thompson DL Jr, Waller CA, Cartmill JA. Hormonal Patterns in Normal and Hyperleptinemic Mares in Response to Three Common Feeding‐Housing Regimens. Journal of Animal Science 85 (2007): 2873–2881.
    doi: 10.2527/jas.2007-0182pubmed: 17591706google scholar: lookup
  16. Berryhill EH, Magdesian KG, Tadros EM, Edman JE. Effects of Age on Serum Glucose and Insulin Concentrations and Glucose/Insulin Ratios in Neonatal Foals and Their Dams During the First 2 Weeks Postpartum. Veterinary Journal 246 (2019): 1–6.
    doi: 10.1016/j.tvjl.2019.01.013pubmed: 30902183google scholar: lookup
  17. Rohrbach BW, Stafford JR, Willis RS. Diagnostic Frequency, Response to Therapy and Long‐Term Prognosis Among Horses and Ponies With Cushing's Disease, 1993–2004. Journal of Veterinary Internal Medicine 26 (2012): 1027–1034.
    doi: 10.1111/j.1939-1676.2012.00932.xpubmed: 22524260google scholar: lookup
  18. Pongratz MC, Graubner C, Eser MW. Equines Cushing Syndrom Wirkungen Einer Langzeittherapie mit Pergolide. Pferdeheilkunde 26 (2010): 598–603.
  19. Horn R, Bamford NJ, Afonso T. Factors Associated With Survival, Laminitis and Insulin Dysregulation in Horses Diagnosed With Equine Pituitary Pars Intermedia Dysfunction. Equine Veterinary Journal 51 (2019): 440–445.
    doi: 10.1111/evj.13041pubmed: 30417404google scholar: lookup
  20. van der Kolk JH. Diseases of the Pituitary Gland, Including Hyperadrenocorticism. in Metabolic and Endocrine Problems of the Horse, ed. Watson TD (WB Saunders, 1998), 41–59.
  21. Ireland JL, Clegg PD, McGowan CM. Factors Associated With Mortality of Geriatric Horses in the United Kingdom. Preventive Veterinary Medicine 101 (2011): 204–218.
    doi: 10.1016/j.prevetmed.2011.06.002pubmed: 21733586google scholar: lookup
  22. van Proosdij R, Frietman S. Retrospective Analysis of Cause‐Of‐Death at an Equine Retirement Center in The Netherlands Over an Eight‐Year Period. Journal of Equine Veterinary Science 110 (2022): 103824.
    doi: 10.1016/j.jevs.2021.103824pubmed: 34843889google scholar: lookup
  23. Peters DF, Erfle JB, Slobojan GT. Low Dose Pergolide Mesylate Treatment for Equine Hypophyseal Adenomas (Cushing's Syndrome). Proceedings of the American Association of Equine Practitioners 41 (1995): 154–155.
  24. Schott HC, Coursen CL, Eberhart SW. The Michigan Cushing's Project. Proceedings of the AAEP 47 (2001): 22–24.
  25. Donaldson MT, LaMonte BH, Morresey P. Treatment With Pergolide or Cyproheptadine of Pituitary Pars Intermedia Dysfunction (Equine Cushing's Disease). Journal of Veterinary Internal Medicine 16 (2002): 742–746.
    doi: 10.1892/0891-6640(2002)016<0742:twpoco>2.3.co;2pubmed: 12465775google scholar: lookup
  26. Perkins GA, Lamb S, Erb HN. Plasma Adrenocorticotropin (ACTH) Concentrations and Clinical Response in Horses Treated for Equine Cushing's Disease With Cyproheptadine or Pergolide. Equine Veterinary Journal 34 (2002): 679–685.
    doi: 10.2746/042516402776250333pubmed: 12455838google scholar: lookup
  27. Tadros EM, Fowlie JG, Refsal KR, Marteniuk J, Schott HC. Association Between Hyperinsulinaemia and Laminitis Severity at the Time of Pituitary Pars Intermedia Dysfunction Diagnosis. Equine Veterinary Journal 51 (2019): 52–56.
    doi: 10.1111/evj.12963pubmed: 29761574google scholar: lookup
  28. Galinelli NC, Bamford NJ, Erdody ML. Effect of Pergolide Treatment on Insulin Dysregulation in Horses and Ponies With Pituitary Pars Intermedia Dysfunction. Equine Veterinary Journal 56 (2025).
    doi: 10.1111/evj.14468pubmed: 39967360google scholar: lookup
  29. Innerå M, Petersen AD, Desjardins DR, Steficek BA, Rosser EJ Jr, Schott HC. Comparison of Hair Follicle Histology Between Horses With Pituitary Pars Intermedia Dysfunction and Excessive Hair Growth and Normal Aged Horses. Veterinary Dermatology 24 (2013): 212–217.
    doi: 10.1111/j.1365-3164.2012.01080.xpubmed: 23331700google scholar: lookup
  30. Hague N, Durham AE, Menzies-Gow NJ. Pergolide Dosing Compliance and Factors Affecting the Laboratory Control of Equine Pituitary Pars Intermedia Dysfunction. Veterinary Record 189 (2021): e142.
    doi: 10.1002/vetr.142pubmed: 33759215google scholar: lookup
  31. Menzies-Gow NJ, Banse HE, Duff A. BEVA Primary Care Clinical Guidelines: Diagnosis and Management of Equine Pituitary Pars Intermedia Dysfunction. Equine Veterinary Journal 56 (2024): 220–242.
    doi: 10.1111/evj.14009pubmed: 37795557google scholar: lookup
Subscribe to our newsletter
Join 99,357 horse owners like you who receive our email updates on horse health and nutrition.