Metformin Effects May Be Via Gut, Not Bloodstream
Dissociation of glycemic effect from plasma exposure with gut-restricted metformin
MONDAY, Aug. 24, 2015 (HealthDay News) -- Metformin may act via a predominantly lower bowel-mediated mechanism, according to research published online Aug. 18 in Diabetes Care.
John B. Buse, M.D., Ph.D., from the University of North Carolina School of Medicine at Chapel Hill, and colleagues conducted two studies to assess delayed-release metformin (Met DR). The first study compared the bioavailability of single daily doses of Met DR with immediate-release metformin (Met IR) and extended-release metformin (Met XR) in 20 otherwise healthy volunteers. The second examined glycemic control in 240 individuals with type 2 diabetes mellitus over 12 weeks.
The researchers found that the bioavailability of 1,000 mg Met DR was about half of that of Met IR and Met XR. In the second study, there were significant, clinically relevant, and sustained reductions in fasting plasma glucose levels over 12 weeks with Met DR (600, 800, and 1,000 mg) compared with placebo, with about a 40 percent increase in potency versus Met XR. At 12 weeks, the placebo-subtracted changes from baseline in hemoglobin A1c were consistent with fasting plasma glucose changes. Treatments were generally well tolerated.
"Dissociation of the glycemic effect from plasma exposure with gut-restricted Met DR provides strong evidence for a predominantly lower bowel-mediated mechanism of metformin action," the authors write.
Several authors disclosed financial ties to pharmaceutical companies, including Elcelyx Therapeutics, which funded the study.