Janumet XR is a combination product prescribed to treat type 2 diabetes. Because it contains two diabetes medications, it works to control blood sugar levels in a couple of different ways. It helps to decrease the amount of sugar made by the liver and increase the amount of insulin produced in response to meals. Side effects may include headaches, diarrhea, and common cold symptoms.
Janumet® XR (sitagliptin and metformin extended-release) is a prescription medication used in combination with an appropriate diet and regular exercise to treat adults with type 2 diabetes. It contains a combination of two diabetes medicines: sitagliptin (Januvia®) and metformin extended-release (Glucophage XR®, Glutametz®, or Fortamet®).
Regular Janumet (sitagliptin and metformin) is similar to Janumet XR, but contains immediate-release metformin instead of the extended-release formulation. Because it does not contain an extended-release version, regular Janumet must be taken twice a day.
Janumet XR is made by Merck Sharp & Dohme Corp.
Janumet XR itself has not been studied in clinical trials. Studies have looked at the effects of the combination of immediate-release metformin and sitagliptin on short-term and long-term blood sugar control. Immediate-release metformin and sitagliptin are the two active medicines contained in regular Janumet.
As mentioned, Janumet XR contains an extended-release form of metformin (metformin ER). Clinical studies have shown that metformin ER is as effective as the immediate-release forms.
Effects on Hemoglobin A1c
HbA1c is a test used to measure long-term blood sugar control. People without diabetes usually have HbA1c results that are less than 6 percent, while people with diabetes have higher results. Studies have shown that the higher the HbA1c, the greater the chance for developing long-term problems related to diabetes, such as heart, eye, nerve, and kidney problems.
In a clinical study, people with diabetes that was not well controlled with diet and exercise were able to reduce their HbA1C by 1.4 percent to 1.9 percent, on average, after taking sitagliptin and metformin for 24 weeks. As might be expected, higher doses resulted in greater Hb1Ac reductions. In comparison, people taking metformin alone lowered their HbA1c by 0.8 percent to 1.1 percent, while those taking sitagliptin alone lowered their HbA1c by 0.7 percent.
Effects on Blood Sugar Levels
In the same study, people given metformin with sitagliptin had a lowering of their fasting blood sugar by 47 mg/dL to 64 mg/dL, on average. In comparison, metformin alone lowered fasting blood glucose by 27 mg/dL to 29 mg/dL, on average, and sitagliptin alone by 17 mg/dL, on average.