Medication Monitor

Generic Name (Trade Name—Company)
February 3, 2012

Sitagliptin/extended-release metformin

(Janumet XR—Merck)
Once-daily formulation now available


Management of type 2 diabetes  

Merck announced FDA approval of its combination tablet containing sitagliptin and extended-release metformin as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes when treatment with combination therapy is appropriate. This new combination offers patients a once-daily treatment option along with the original formulation using immediate-release metformin (Janumet), which is dosed twice daily.

Approval was based upon a clinical bioequivalence study demonstrating that administration of Janumet XR was equivalent to coadministration of corresponding doses of the two individual medications, sitagliptin and extended-release metformin.

When switching patients from Janumet to Janumet XR, maintain the same total daily dose. In addition, educate patients given the new formulation to take the tablets once daily with a meal, preferably in the evening, and not to split, break, crush, or chew the tablets before swallowing. Janumet XR will be marketed in strengths of 100 mg/1,000 mg, 50 mg/500 mg, and 50 mg/1,000 mg of sitagliptin/extended-release metformin.