After reading about combining oral antidiabetics, such as acarbose (Precose) and sitagliptin (Januvia) (Item 113-12), I wonder if there are any data regarding the use of sitagliptin and glyburide (Glynase, Diabeta, Micronase)?
—Tom Perry, MD, Phoenix
As was true of the scenario using acarbose and sitagliptin in combination, I could find no published data on the use of sitagliptin (a dipeptidyl peptidase-4 [DPP-4] inhibitor) with glyburide, a sulfonylurea. Merck, the maker of Januvia, notes that the use of Januvia in combination with medications known to cause hypoglycemia, such as sulfonylureas or insulin, has not been adequately studied and research is ongoing (www.januvia.com/sitagliptin/januvia/hcp/moa/index.jsp. Accessed March 12, 2008). Since both sulfonylureas and DPP-4 inhibitors stimulate the release of insulin from pancreatic beta cells by different mechanisms of action, I would hypothesize that there could be a significant risk for hypoglycemia when they are used in combination. Exenatide (Byetta), an incretin mimetic, similarly increases the synthesis and release of pancreatic insulin, and this agent is approved for use with sulfonylureas, so I suspect this will ultimately be the case for sitagliptin, albeit with caution.
—daniel G. Tobin, MD (114-26)