Janumet 50/500 is a prescription medication that combines sitagliptin phosphate (50 mg) and metformin HCl (500 mg) in tablet form. This combination medication is used to help control blood sugar levels in patients with type 2 diabetes. The package contains 56 tablets. Janumet is manufactured by MSD (Merck Sharp & Dohme). The medication combines two diabetes medicines - sitagliptin which belongs to a class of drugs called DPP-4 inhibitors, and metformin which helps reduce glucose production in the liver and improves insulin sensitivity. Each tablet contains 50 mg sitagliptin phosphate and 500 mg metformin hydrochloride.