For newly diagnosed type 2 diabetes patients, metformin is the first-line drug of choice. It can be used alone, in combination with other oral antidiabetic drugs, or in addition to insulin. Its precise mechanism of action is as of yet unknown, but a new study published in Diabetes Care posits that it works in the gut. It has previously been suspected of exerting an effect in the bloodstream.
The published study details results from phase 1 and phase 2 trials of Metformin Delayed Release (Metformin DR). This formulation limits the absorption of metformin into the blood and targets the lower bowel. This is clinically significant because it may allow patients who cannot take metformin to begin treatment. Up to 40% of patients with diabetes cannot take metformin due to kidney damage. Impaired renal function leads to accumulation of metformin in the blood, resulting in toxicity such as lactic acidosis.
Despite limiting absorption into circulation, the drug still demonstrated significant serum glucose reduction. The phase 1 study compared Metformin DR to immediate-release and extended-release formulations. Metformin DR was present in the bloodstream at half the levels of the older formulations. The phase 2 study compared Metformin DR to placebo and extended-release metformin in type 2 diabetic patients. It showed a 40% increase in glucose-lowering potency compared to the older formulation. The treatment was typically well-tolerated with an adverse-effects profile that mirrored currently available metformin formulations. The phase 1 study had 20 volunteers, whereas the phase 2 study has 240 type 2 diabetic patients and was multicenter. The phase 2 study tested several doses, including 600, 800, and 1,000 mg of Metformin DR once daily.
Overall, the results of these studies are promising. This new formulation of metformin may prove useful for renally impaired patients who represent a large portion of diabetic patients. In addition, by focusing the delivery of the drug to the theorized site of action, Metformin DR may prove more efficacious in general than the older formulations.
- Metformin DR is a new formulation of metformin that limits absorption of the drug into the bloodstream and focuses delivery in the lower gut.
- 40% of patients have renal damage that limits their ability to take metformin. By reducing the amount of metformin in the bloodstream, Metformin DR may prove useful in renally-impaired patients because it does not undergo major renal excretion due to limited circulation.
- The studies of Metformin DR also imply that metformin acts in the gut to reduce blood glucose, not systemically. This is confirmed because Metformin DR maintains the potent glucose lowering effects of older formulations of metformin.
“New Metformin Could Help 40-percent of Diabetes Patients That Currently Can’t Take Metformin.” Published 20 August 2015. Diabetes Care