The effect of metformin on measurements of insulin sensitivity and beta cell response in 18 horses and ponies with insulin resistance.
BACKGROUND
Laminitis in equids is a very common debilitating disease, and insulin resistance (IR) and hyperinsulinaemia are increasingly recognised as important predisposing factors. Pharmacological modification of IR and hyperinsulinaemia might reduce the risk of laminitis.


OBJECTIVE
Metformin, a drug commonly prescribed for treatment of human IR, may also decrease IR in equids.


METHODS
Eighteen horses and ponies with IR and recurrent laminitis were treated with 15 mg/kg bwt metformin per os q. 12 h. Each animal served as its own control by comparing pre- and post treatment proxies for IR, insulin sensitivity (IS) and pancreatic beta cell function while controlling for possible dietary and managemental influences on IR.


RESULTS
Evidence of significantly improved IS and decreased pancreatic beta cell secretion was found following metformin treatment. The magnitude of effect was greater at earlier resampling (6-14 days) than at later times (23-220 days). Apparent subjective clinical benefits were good but less favourable than effects on IR.


CONCLUSIONS
Metformin is safe and appears to increase IS in equids.


CONCLUSIONS
Metformin may be indicated as a treatment for IR in equids. Further studies are required to define appropriate selection of subjects warranting therapy, dosing schedule and pharmacokinetics.
Durham
A E
AE
The Liphook Equine Hospital, Forest Mere, Liphook, Hampshire GU30 7JG, UK.
Rendle
D I
DI
Newton
J E
JE
D000818:Animals; D019540:Area Under Curve; D001786:Blood Glucose / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule / Q000662:veterinary; D005260:Female; D005534:Foot Diseases / Q000097:blood / Q000209:etiology / Q000517:prevention & control / Q000662:veterinary; D006734:Horse Diseases / Q000188:drug therapy* / Q000517:prevention & control; D006736:Horses; D006946:Hyperinsulinism / Q000150:complications / Q000188:drug therapy / Q000662:veterinary*; D007004:Hypoglycemic Agents / Q000493:pharmacokinetics / Q000627:therapeutic use*; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D007333:Insulin Resistance; D050417:Insulin-Secreting Cells / Q000187:drug effects* / Q000378:metabolism; D007794:Lameness, Animal / Q000097:blood / Q000209:etiology / Q000517:prevention & control; D008297:Male; D008687:Metformin / Q000493:pharmacokinetics / Q000627:therapeutic use*; D016896:Treatment Outcome
D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin; D008687:Metformin