Insulin dysregulation (ID) is prevalent in senior equids, affecting approximately 30% of horses with pituitary pars intermedia dysfunction (PPID). Left untreated, this complex endocrine disorder can lead to laminitis, a painful and life-threatening condition.

Previous clinical trials have suggested that the sodium-glucose co-transporter 2 (SGLT2) inhibitor canagliflozin might help treat ID. In a new study, researchers in Sweden evaluated the drug’s short-term effects on postprandial glucose and insulin responses in horses and ponies with ID.

Study Population

The study included 70 privately owned horses and ponies with ID confirmed by an oral sugar test. Sixty-two horses (89%) were aged 10 years or older. Eleven horses (16%) had been diagnosed with PPID and were receiving pergolide mesylate treatment. Sixteen horses (23%) were being treated with non-steroidal anti-inflammatory drugs.

Each horse received oral canagliflozin (0.4-0.6 mg/kg body weight) once daily for three weeks. The horses remained in their home environments throughout the study, and owners maintained consistent feeding, exercise, and turnout routines.

Study Findings

Researchers recorded each horse’s body weight, clinical biochemical parameters, and glucose and insulin concentrations during a feed challenge test (FCT) before and after the three-week treatment period. They found that:

  • Mean insulin concentrations during the FCT decreased after three weeks of treatment with canagliflozin, from 304.4 ± 25.4 to 171.2 ± 25.9 μIU/mL.
  • Insulin concentrations did not decrease in 13% (9/70) of horses following treatment.
  • After three weeks, 90% of horses developed hypertriglyceridemia (abnormally high levels of triglycerides—a type of fat—in the blood), and 9% had triglyceride concentrations above the threshold for hyperlipemia (the disease caused by hyperlipidemia, or the abnormally high concentration of fats or lipids in the blood). This increase was associated with clinical signs in only one horse.
  • Canagliflozin treatment was associated with elevated liver enzyme (GLDH and GGT) levels, although the clinical significance of these changes is unclear.
  • Sixty-five percent of horses lost weight, while 17% experienced no change and 17% gained weight.

Final Thoughts

In this study, short-term canagliflozin treatment was associated with a significant overall reduction in insulin concentrations in horses with severe insulin dysregulation, although a subset of horses did not respond. Treatment was also associated with hypertriglyceridemia and increased liver enzyme levels, though the extent of these changes varied among individuals.

The authors cautioned that these findings must be interpreted carefully because the study lacked a control group, making it impossible to definitively attribute the observed changes to canagliflozin administration. They also emphasized the importance of thorough follow-up testing to evaluate both the efficacy and safety of treatment.

“Achieving sufficient diet and management corrections to adequately reduce hyperinsulinemia in severely ID horses is often immensely challenging,” the study authors wrote. “Novel pharmacotherapies such as SGLT2 inhibitors offer a promising adjunct to lifestyle modification for reducing hyperinsulinemia.”

Reference

Hällbom M, Lindåse ST, Wartel M, Bröjer J. Short-term clinical responses in horses and ponies treated with canagliflozin: A clinical field study. Equine Vet J. 2026. https://doi.org/10.1002/evj.70181

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  • Carly Sisson is a horse owner (including one senior horse, aged 22) and the managing editor of EquiManagement and My Senior Horse.

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