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Home / Equine Research Bank / Equine Vet J / The effect of pre-dosing with metformin on the insulin respo...
Equine veterinary journal2023; doi: 10.1111/evj.13979

The effect of pre-dosing with metformin on the insulin response to oral sugar in insulin-dysregulated horses.

Abstract: A single dose of metformin administered 1 h prior to oral glucose challenge was previously shown to reduce insulinaemic responses in horses with experimentally-induced insulin dysregulation (ID). Targeted administration could be useful for controlling post-prandial hyperinsulinaemia in horses with naturally-occurring ID.
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Publication Date: 2023-08-06 PubMed ID: 37545128DOI: 10.1111/evj.13979Google Scholar: Lookup
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  • Journal Article

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.
  • Metformin is a medication that’s been shown to reduce insulin responses in horses when given 1 hour before a glucose challenge. This was tested in horses with artificially induced insulin problems.
  • The idea is that if metformin can help control insulin spikes after eating in horses with natural insulin problems, it could be a beneficial treatment.

Objectives:

  • The main goal was to see how horses with naturally-occurring insulin problems respond to a sugar challenge when given metformin at different times before the challenge.
  • The hypothesis was that if these horses are given metformin before the sugar challenge, their insulin responses would be lower.

Study Design:

  • This was a randomized cross-over experiment, meaning the same horses were tested under different conditions to compare results.

Methods:

  • Eight horses, owned by the university and with natural insulin issues, were given a sugar challenge at different times (1, 2, and 6 hours) after taking a single dose of metformin. They were also tested 1 hour after being given a placebo (water).
  • A week was left between each test to ensure the effects of the previous test were gone.
  • The study spanned 3 weeks.
  • Scientists measured the levels of insulin, C-peptide (another marker of insulin production), and glucose in the blood at different times after giving the horses light corn syrup (the sugar challenge).

Results:

  • There was no significant difference in blood glucose, insulin, or C-peptide levels when horses were given metformin compared to the placebo.
  • For example, when tested 1 hour after metformin, the insulin levels were not significantly different than when given a placebo.

Limitations:

  • The sample size was small, so it might not catch small changes in insulin levels due to metformin.
  • The results only apply to a single dose of metformin given before a meal, so it doesn’t tell us what might happen with regular metformin use.

Conclusions:

  • Based on this study, giving metformin to horses with natural insulin problems before a meal doesn’t seem to help control their insulin levels.
  • Therefore, this specific method of using metformin isn’t recommended for managing high insulin levels after meals in these horses.

Cite This Article

APA
Colmer SF, Adams AA, Adam E, Miller R, Stefanovski D, Kulp JC, van Eps A. (2023). The effect of pre-dosing with metformin on the insulin response to oral sugar in insulin-dysregulated horses. Equine Vet J. https://doi.org/10.1111/evj.13979

Publication

Equine veterinary journal
ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English

Researcher Affiliations

Colmer, Sarah F
  • Department of Clinical Studies-New Bolton Center, The University of Pennsylvania School of Veterinary Medicine, Kennett Square, Pennsylvania, USA.
Adams, Amanda A
  • Department of Veterinary Science, Gluck Equine Research Center, The University of Kentucky College of Agriculture, Food and Environment, Lexington, Kentucky, USA.
Adam, Emma
  • Department of Veterinary Science, Gluck Equine Research Center, The University of Kentucky College of Agriculture, Food and Environment, Lexington, Kentucky, USA.
Miller, Rachel
  • Department of Clinical Sciences, Lincoln Memorial University College of Veterinary Medicine, Harrogate, Tennessee, USA.
Stefanovski, Darko
  • Department of Clinical Studies-New Bolton Center, The University of Pennsylvania School of Veterinary Medicine, Kennett Square, Pennsylvania, USA.
Kulp, Jeaneen C
  • Department of Clinical Studies-New Bolton Center, The University of Pennsylvania School of Veterinary Medicine, Kennett Square, Pennsylvania, USA.
van Eps, Andrew
  • Department of Clinical Studies-New Bolton Center, The University of Pennsylvania School of Veterinary Medicine, Kennett Square, Pennsylvania, USA.

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Citations

This article has been cited 4 times.
  1. Anger-Håål C, Fjordbakk CT, Ekstrand C, Skedsmo FS, Rørtveit R. Sodium-glucose transporters SGLT1 and SGLT2 in equine renal, hepatic and pancreatic tissue. BMC Vet Res 2025 Dec 17;22(1):36.
    doi: 10.1186/s12917-025-05173-1pubmed: 41408266google scholar: lookup
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  3. Michanek P, Bröjer J, Lilliehöök I, Fjordbakk CT, Löwgren M, Hedeland M, Bergquist J, Ekstrand C. Pharmacokinetics and Alterations in Glucose and Insulin Levels After a Single Dose of Canagliflozin in Healthy Icelandic Horses. J Vet Pharmacol Ther 2025 Jan;48 Suppl 1(Suppl 1):41-49.
    doi: 10.1111/jvp.13476pubmed: 39113254google scholar: lookup
  4. Lindåse S, Nostell K, Forslund A, Bergsten P, Bröjer J. Short-term effects of canagliflozin on glucose and insulin responses in insulin dysregulated horses: A randomized, placebo-controlled, double-blind, study. J Vet Intern Med 2023 Nov-Dec;37(6):2520-2528.
    doi: 10.1111/jvim.16906pubmed: 37864426google scholar: lookup
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