What is Janumet (sitagliptin and metformin)?

From the Guidelines

Janumet is a prescription medication that combines two diabetes drugs, sitagliptin and metformin, in a single tablet to help control blood sugar levels in adults with type 2 diabetes. Sitagliptin belongs to a class of drugs called DPP-4 inhibitors, which work by increasing insulin production when blood sugar is high and decreasing the amount of sugar made by the liver 1. Metformin, the other component, reduces glucose production in the liver and helps the body respond better to insulin. Janumet is typically prescribed when diet and exercise alone aren't enough to control blood sugar, or when patients are already taking both medications separately. It's usually taken twice daily with meals to reduce stomach upset, a common side effect of metformin. The medication comes in different strengths, including 50/500 mg, 50/1000 mg, and 100/1000 mg of sitagliptin/metformin.

Key Points to Consider

• Patients should be aware that Janumet may cause side effects such as stomach discomfort, diarrhea, and upper respiratory infections.
• In rare cases, metformin can cause lactic acidosis, a serious condition, so kidney function should be monitored while taking this medication 1.
• Metformin is effective and safe, is inexpensive and widely available, and reduces risks of microvascular complications, cardiovascular events, and death 1.
• The principal side effects of metformin are gastrointestinal intolerance due to bloating, abdominal discomfort, and diarrhea; these can be mitigated by gradual dose titration and/or using extended-release formulation 1.

Monitoring and Precautions

• Kidney function should be monitored while taking Janumet, as metformin may cause lactic acidosis in rare cases 1.
• Patients with an estimated glomerular filtration rate (eGFR) of 30-45 mL/min/1.73 m² should be monitored closely for periodic decreases in eGFR, which may increase the risk of lactic acidosis 1.
• Vitamin B12 levels should be tested periodically, as metformin use is associated with vitamin B12 deficiency and worsening of symptoms of neuropathy 1.

From the FDA Drug Label

SITAGLIPTIN/METFORMIN 50/850MG

Janumet is a combination of sitagliptin and metformin, two oral antidiabetic drugs.

• Sitagliptin is a dipeptidyl peptidase-4 (DPP-4) inhibitor.
• Metformin is a biguanide. Janumet is used to treat type 2 diabetes 2.

From the Research

What is Janumet

• Janumet is a fixed-dose combination of sitagliptin and metformin, used to treat type 2 diabetes 3.
• It combines the actions of sitagliptin, a dipeptidylpeptidase-4 inhibitor, and metformin, a biguanide compound, to improve glucose control without inducing hypoglycemia or weight gain 3.

Mechanism of Action

• Sitagliptin works by inhibiting the degradation of incretin hormones, resulting in increased insulin secretion and decreased glucagon secretion in a glucose-dependent manner 4.
• Metformin reduces hepatic glucose production and slightly improves insulin sensitivity 3.

Bioequivalence and Pharmacokinetics

• The sitagliptin/metformin fixed-dose combination tablets (Janumet) have been shown to be bioequivalent to co-administration of corresponding doses of sitagliptin and metformin as individual tablets 5.
• The pharmacokinetic parameters of sitagliptin and metformin were similar when administered as a fixed-dose combination or as individual tablets 5.

Efficacy and Safety

• Janumet has been shown to be effective in improving glycemic control in patients with type 2 diabetes, with a safety profile similar to that of metformin 3, 6.
• Sitagliptin, a component of Janumet, has been shown to be well-tolerated, with common side effects including gastrointestinal complaints, and a low risk of hypoglycemia 4, 7.