Janumet XR 50/500mg is a prescription medication that combines sitagliptin and metformin HCl in an extended-release formulation. This combination therapy is used to help control blood sugar levels in adults with type 2 diabetes mellitus. The package contains 56 tablets. This medication contains two active ingredients - sitagliptin 50mg and metformin hydrochloride 500mg in an extended-release (XR) formulation. The XR formulation allows for once-daily dosing. As with all prescription medications, this should only be taken under the direction and supervision of a healthcare provider.