Hi Mary,   Thank you for your question. Glucovance is a combination medication, consisting of metformin and glyburide. Metformin is processed and eliminated by the kidneys, so if your mother's kidney function is decreasing, it's good that her doctor stopped it. The metformin most likely did not cause the worsening kidney function. Diabetes itself is hard on a lot of organs, most notably the kidney and the eye. Her worsening kidney function could simply be a result of years of diabetes (and it's even possible that she may had diabetes for some time before it was diagnosed). Whatever the cause of the decreased kidney function, it's good that her doctor discontinued the metformin. Glyburide is the other component of Glucovance, and it can be used even in patients with reduced kidney function. She may need a higher dose of the glyburide now that the metformin has been removed from the equation, but I'm sure her doctor will keep an eye on what adjustments need to be made to keep her diabetes under control. I hope this helps!   Best of luck to you and your mom! Casey