Metformin and repaglinide are oral diabetes medications that help control blood sugar levels. Repaglinide works by causing the pancreas to produce insulin. Metformin works by decreasing glucose (sugar) production in the liver and decreasing absorption of glucose by the intestines. The combination of metformin and repaglinide is used together with diet and exercise to treat type 2 diabetes. Metformin and repaglinide may also be used for other purposes not listed in this medication guide.