Pharmacokinetics of Metformin in Combination With Sitagliptin in Adult Horses After Enteral Administration.
Authors: Cárceles-Rodríguez Carlos M, Fernández-Varón Emilio, Martín-Gimenez Tamara, Aguirre Carla, Arion Alexandra, Rodríguez María J, Ayala Ignacio
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Metformin and Sitagliptin Pharmacokinetics in Horses Insulin dysregulation remains a significant metabolic challenge in equine practice, and emerging evidence suggests that incretin hormones may play a role in its pathogenesis—prompting investigation into human antidiabetic therapies as potential treatment options. Cárceles-Rodríguez and colleagues administered a combined metformin (15 mg/kg) and sitagliptin (1.5 mg/kg) preparation via intragastric route to six healthy Purebred Spanish horses, collecting blood samples over 48 hours and measuring plasma drug concentrations using high-performance liquid chromatography to establish pharmacokinetic profiles. Metformin demonstrated rapid absorption and clearance with a half-life of 2.9 hours and peak plasma concentration of 442 ± 84 mg/L at 0.9 hours, whilst sitagliptin showed slower elimination (half-life 21 hours) and peaked at 94 ± 14 mg/L within 1.3 hours; critically, the combination was well tolerated with no observed adverse effects. These pharmacokinetic data provide the foundational evidence necessary for considering this drug combination in clinical management of equine insulin dysregulation, though practitioners should recognise that efficacy and safety in naturally-occurring endocrine disease remain to be established through further targeted trials. The differing elimination rates suggest that twice-daily metformin dosing coupled with once-daily sitagliptin may represent a practical dosing strategy, pending clinical validation.
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Practical Takeaways
- •Metformin and sitagliptin can be safely administered together orally to horses; metformin requires more frequent dosing (shorter half-life) while sitagliptin provides sustained effect over 24 hours
- •This combination appears well-tolerated in healthy horses and may warrant consideration as a treatment option for equine insulin dysregulation, pending further efficacy studies in clinical cases
- •Current evidence is limited to pharmacokinetics in healthy horses; consult with an equine internist before using this combination in horses with metabolic disorders, as clinical effectiveness has not yet been established
Key Findings
- •Metformin half-life was 2.9 hours with Cmax of 442 ± 84 mg/L at 0.9 hours after intragastric administration at 15 mg/kg
- •Sitagliptin half-life was 21 hours with Cmax of 94 ± 14 mg/L at 1.3 hours after intragastric administration at 1.5 mg/kg
- •The combination of metformin and sitagliptin was well tolerated with no observed adverse effects in healthy horses
- •Results support further investigation of this drug combination for treating insulin dysregulation in horses, though efficacy studies in affected animals are needed