Hello, ISTAMET  is a combination of two drugs - Sitagliptin and Metformin and is given as an adjunct to insulin and not as replacement of injectable insulin. Sitagliptin inhibits an enzyme called DPP4, which usually destroys a hormone called GLP1 in the body. So, more GLP1 is available in the blood which helps in adequate release of Insulin from pancreas which in turn helps lowering blood glucose. On the other hand, Metformin decreases Insulin resistance in the body (mainly in muscles and liver). Insulin resistance is an integral part of Type 2 diabetes. Once the insulin resistance is lowered, the body responds well to its own Insulin resulting in lowering of blood glucose. Combining both tablets is a very good regimen to control diabetes. You should take this drug along with injectable insulin. It doesn t adversely affect kidney functions and rather can be given in patients suffering from renal insufficiency,albeit in modified dosages. I think glucovit and ISTAMET are same. Please check the ingredients of both the medicines. You must take both ISTAMET and INJECTABLE INSULIN for better response. Discuss with your doctor about it. Thanks