SOURCES
Metformin is available in single-ingredient preparations as well as in combination with other antidiabetic agents. Under the trade name Glucophage (Bristol-Myers Squibb) and in several generic formulations, metformin is available as tablets containing 500, 850, or 1,000 mg of metformin hydrochloride. Glucophage XR, the extended-release formulation, contains 500 or 750 mg of metformin hydrochloride. Two other metformin-only products available in the United States are Riomet (Ranbaxy Pharmaceuticals), a liquid oral formulation containing 500 mg/5 ml of metformin hydrochloride, and Fortamet (First Horizon Pharmaceutical) 500- or 1,000-mg extended-release tablets.
Blood glucose, triglycerides and total cholesterol concentrations
When comparing the basal time blood glucose [control group: median 5.93 mmol/L (interquartile range 4.1–6.2), metformin group: 6.38 mmol/L (5.3–6.9)], triglycerides [control group: 1.6 mmol/L (1.3–2.6), metformin group: 2.3 mmol/L (1.9–3.7)] and total cholesterol concentrations [control group: 7.8 mmol/L (6.1–11.5), meformin group: 9.9 mmol/L (7.3–12.3)] between the groups, no significant differences were observed ( and ). In the metformin group, blood glucose (P < 0.01), triglycerides (P < 0.05) and total cholesterol (P < 0.01) concentrations were significantly reduced after 3 months of treatment ( ).
| Parameter | Control group | Metformin group | ||
| Basal | 3 months | Basal | 3 months | |
|---|---|---|---|---|
| Glucose (mmol/L) | 5.93(4.1-6.2) | 5.71(5.2-6.8) | 6.38(5.3-6.9) | 4.76**,a(4.1-5.5) |
| Triglycerides (mmol/L) | 1.6(1.3-2.6) | 2.0(1.6-2.6) | 2.3(1.9-3.7) | 1.1*,b(0.7-1.8) |
| Total cholesterol (mmol/L) | 7.8(6.1-11.5) | 7(5.6-7.8) | 9.9(7.3-12.3) | 7.2**(6.2-10.7) |
| Insulin (pmol/L) | 185(97-406) | 165*(80-340) | 180(90-430) | 110**,c(75-299) |
| UCCR (10-6) | 74(22.4-282) | 15***(8.5-30) | 55(25-675) | 13***(7-280) |
In the control group, no significant differences were observed between the basal time measurements and those taken at 3 months for the three variables analysed. Comparing the concentrations between each group at 3 months, only blood glucose [control group: 5.71 mmol/L (5.2–6.8), metformin group: 4.76 mmol/L (4.1–5.5)] and triglycerides concentrations [control group: 2.0 mmol/L (1.6–2.6), metformin group: 1.1 mmol/L (0.7–1.8)] differed significantly (P < 0.01 and P < 0.05, respectively), with lower concentrations than the control group.
Analysing the individual variation, the blood glucose concentration decreased in 13/13 dogs in the metformin group, and the triglycerides and total cholesterol concentrations decreased in 11/13 dogs (84.61%), with the concentrations increasing in the remaining two dogs. In the control group, blood glucose levels were decreased in 4/10 dogs (40%), increased in 4/10 dogs (40%) and remained constant in 2/10 dogs (20%). Triglycerides concentrations decreased in 3/10 dogs (30%), increased in 2/10 dogs (20%) and remained constant in 5/10 dogs (50%). Total cholesterol concentrations decreased in 5/10 dogs (50%) and remained constant in 5/10 dogs (50%) of the control group.
What is metformin used for in dogs?
Metformin reduces hepatic glucose production and insulin resistance of the skeletal muscle and adipose tissue. The aim of this study was to evaluate the effects of metformin on the control of metabolic disorders of dogs with hyperadrenocorticism (HAC).