Efficacy of trilostane for the treatment of equine Cushing’s syndrome.
Abstract: Trilostane, a competitive 3-beta hydroxysteroid dehydrogenase inhibitor, has been used successfully to control clinical signs and cortisol excess in canine pituitary dependent hyperadrenocorticism. Objective: Trilostane was evaluated for its efficacy in resolving clinical and clinicopathological abnormalities of equine Cushing's syndrome (ECS) and to assess its safety. Methods: Twenty horses (mean age 21 years) diagnosed with ECS were followed for 1 or 2 years. Affected horses received 0.4-1 mg/kg (mean 0.5 mg/kg) trilostane once daily. Results: Clinical signs assessed over 1 or 2 years, showed a reduction in lethargy in all horses post treatment. Polyuria and/or polydipsia, present in 11 horses, was reduced in all after treatment. Recurrent or chronic laminitis, present in 16 horses, improved in 13/16 (81%) of cases. There were no side effects reported. Combined dexamethasone suppression and thyrotropin releasing hormone (TRH) stimulation tests were significantly different before and 30 days following therapy. There was a significant reduction (P = 0.01) of cortisol following TRH administration before (160 +/- 53.0 nmol/l) and after (130 +/- 46.1 nmol/l) trilostane. Conclusions: Trilostane caused improvement in clinical signs in horses, without side effects, and a corresponding decrease in cortisol response to TRH administration. Conclusions: Trilostane may be a useful therapy for the treatment of ECS. Further work comparing the effects of trilostane and pergolide is warranted.
Publication Date: 2003-07-26 PubMed ID: 12880011DOI: 10.2746/042516403776014271Google Scholar: Lookup
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- Journal Article
Summary
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This study looked at the effects of a medication called trilostane on horses with Cushing’s syndrome. The researchers found the drug to be effective in reducing symptoms and positively affecting laboratory measures of the disease, with no reported side effects.
Overview and Purpose of the Study
- This research aimed to investigate the effectiveness of trilostane, a medication originally designed for dogs with comparable health issues, as a viable treatment option for horses with Cushing’s syndrome.
- The study’s objective was to track changes in symptoms and disease markers in horses after they received trilostane treatments.
Methods Employed
- The researchers studied 20 horses diagnosed with the disease, monitoring each for one or two years.
- Affected horses were given doses of trilostane, which interferes with the body’s production of certain types of hormones, daily, and the progression of their disease was tracked.
Findings of the Study
- The study reported an overall decrease in Cushing’s syndrome symptoms such as lethargy, excessive urination and thirst (polyuria and/or polydipsia), and recurring laminitis, a painful inflammation in a horse’s foot.
- Furthermore, lab tests showed significant changes in hormone levels, indicating a positive response to the trilostane treatment.
- The researchers did not document any adverse side effects from the trilostane treatment throughout the course of the study.
Conclusions and Recommendations for Further Research
- The study concluded that trilostane significantly improved the clinical symptoms in horses with equine Cushing’s syndrome, reduced cortisol responses, and did so without causing any detected side effects.
- The researchers deemed trilostane a promising treatment for equine Cushing’s syndrome and called for further studies comparing the effects of trilostane and pergolide, a medication commonly used in treating this condition.
Cite This Article
APA
McGowan CM, Neiger R.
(2003).
Efficacy of trilostane for the treatment of equine Cushing’s syndrome.
Equine Vet J, 35(4), 414-418.
https://doi.org/10.2746/042516403776014271 Publication
Researcher Affiliations
- School of Animal Studies, The University of Queensland, Gatton 4343, Australia.
MeSH Terms
- 3-Hydroxysteroid Dehydrogenases / antagonists & inhibitors
- Adrenocorticotropic Hormone / blood
- Animals
- Cushing Syndrome / drug therapy
- Cushing Syndrome / veterinary
- Dihydrotestosterone / analogs & derivatives
- Dihydrotestosterone / therapeutic use
- Enzyme Inhibitors / therapeutic use
- Female
- Horse Diseases / drug therapy
- Horses
- Hydrocortisone / blood
- Male
- Safety
- Treatment Outcome
Citations
This article has been cited 7 times.- Kirkwood NC, Hughes KJ, Stewart AJ. Pituitary Pars Intermedia Dysfunction (PPID) in Horses. Vet Sci 2022 Oct 10;9(10).
- Gehlen H, Schwarz B, Bartmann C, Gernhardt J, Stöckle SD. Pituitary Pars Intermedia Dysfunction and Metabolic Syndrome in Donkeys. Animals (Basel) 2020 Dec 8;10(12).
- To T. Inappropriate lactation in a 15-year-old thoroughbred mare. Can Vet J 2019 Apr;60(4):430-433.
- Haritou SJ, Zylstra R, Ralli C, Turner S, Tortonese DJ. Seasonal changes in circadian peripheral plasma concentrations of melatonin, serotonin, dopamine and cortisol in aged horses with Cushing's disease under natural photoperiod. J Neuroendocrinol 2008 Aug;20(8):988-96.
- Fouché N, Doras C, Schüpbach-Regula G, Scherer A, Freudenschuss B, Gerber V. Association Between Adrenocorticotropic Hormone Concentration and Clinical Signs of Pituitary Pars Intermedia Dysfunction in Swiss and Austrian Equids. J Vet Intern Med 2025 Mar-Apr;39(2):e70008.
- Vaughn SA, Lemons MB, Hart KA. The Effect of Season and Breed on Hypothalamic-Pituitary-Adrenal Axis Hormones, Metabolic Hormones, and Oxidative Markers in Ponies and Horses. J Vet Intern Med 2025 Mar-Apr;39(2):e70047.
- Olaimat AR, Jafarzadehbalagafsheh P, Gol M, Costa AM, Biagini G, Lucchi C. Trilostane: Beyond Cushing's Syndrome. Animals (Basel) 2025 Feb 2;15(3).
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