The Use of Metformin for the Treatment of Equine Metabolic Syndrome

Metformin is a human drug prescribed for the treatment of type II diabetes mellitus. In humans, metformin reduces glucose absorption from the intestine and decreases the amount of glucose produced by the liver (gluconeogenesis). Metformin has been used in horses to counteract the effects of equine metabolic syndrome. However, some studies have shown that intestinal absorption of metformin in horses is poor, and metformin may not improve insulin sensitivity in ponies.

Nine horses were given a feed containing glucose, and their blood concentrations of insulin and glucose were measured for 240 minutes afterward. The test was performed with and without administration of metformin. The horses were treated with a high dose of metformin (30 mg/kg). Results of the study showed that administration of metformin significantly decreased intestinal absorption of glucose and the corresponding insulin response.

This study indicates that metformin may be useful for the treatment of equine metabolic syndrome. For best results, medical therapy should be combined with management practices such as reducing obesity, feeding lower carbohydrate feeds, controlling pasture grazing, and increasing exercise.

Durham, A.E., D.I. Rendle, F. Rutledge, et al. 2012. The effects of metformin hydrochloride on intestinal glucose absorption and use of tests for hyperinsulinaemia. In: Proceedings. Am. Coll. Vet. Intern. Med. 281.