Can Metformin and Sitagliptin (Januvia) be taken together?

From the Guidelines

Yes, Metformin and Januvia (sitagliptin) can be taken together, and this combination is actually quite common in diabetes treatment. These medications work in different ways to help control blood sugar levels. Metformin reduces glucose production in the liver and improves insulin sensitivity, while Januvia helps increase insulin production and decrease glucagon levels by inhibiting the DPP-4 enzyme. The combination is often prescribed when metformin alone doesn't provide adequate blood sugar control. In fact, there's even a combination pill called Janumet that contains both medications.

Key Points to Consider

• Typical dosing might include metformin 500-1000 mg twice daily along with Januvia 100 mg once daily, though your doctor will determine the appropriate doses based on your specific needs.
• It's essential to take these medications as prescribed and monitor for side effects, which may include gastrointestinal issues like nausea or diarrhea (more common with metformin) and potential upper respiratory infections (with Januvia) 1.
• Regular blood sugar monitoring and HbA1c testing will help determine if this combination is effectively controlling your diabetes.
• The choice of medication added to metformin is based on the clinical characteristics of the patient and their preferences, including the presence of established ASCVD or indicators of high ASCVD risk, other comorbidities, and risk for specific adverse drug effects, as well as safety, tolerability, and cost 1.
• A comparative effectiveness meta-analysis suggests that each new class of noninsulin agents added to initial therapy with metformin generally lowers A1C approximately 0.7–1.0% 1.
• The most recent guidelines from 2023 support the use of combination therapy, including metformin and a DPP-4 inhibitor like Januvia, for the management of type 2 diabetes, considering person-specific factors and the need for individualized treatment plans 1.

From the FDA Drug Label

SITAGLIPTIN/METFORMIN 50/850MG

• Combination Therapy: The presence of this combination in the drug label suggests that Sitagliptin (Januvia) and Metformin can be taken together.
• Key Point: The FDA drug label directly supports the use of Sitagliptin and Metformin in combination, as evidenced by the listing of a specific combination dosage. The answer is yes, Metformin and Januvia (Sitagliptin) can be taken together, as indicated by the combination therapy listed in the drug label 2.

From the Research

Combination Therapy with Metformin and Januvia

• Metformin and Januvia (sitagliptin) can be taken together, as evidenced by the FDA approval of a combination tablet of sitagliptin and metformin HCl (Janumet) 3.
• The combination of sitagliptin and metformin has been shown to be safe and effective in improving glycemic control in patients with type 2 diabetes, with a complementary and possibly additive effect 3, 4.
• Clinical trials have demonstrated the efficacy of sitagliptin in combination with metformin in terms of improving glycaemic control, with benefits including reductions in HbA1c, fasting plasma glucose, and 2-h postprandial glucose levels 5, 6.

Efficacy and Safety of Combination Therapy

• A meta-analysis of randomized controlled trials found that DPP-4 inhibitors (including sitagliptin) plus metformin as initial combination therapy was associated with higher reductions in HbA1c and fasting plasma glucose levels compared to metformin monotherapy 6.
• Sitagliptin has been shown to be generally well tolerated, with a low risk of hypoglycaemia and a neutral effect on body weight 5, 7.
• The combination of sitagliptin and metformin has been found to be safe and effective in a broad spectrum of patients with type 2 diabetes, including obese, elderly, and renally impaired patients, as well as those with established cardiovascular disease 7.

Long-term Use and Cardiovascular Safety

• Long-term follow-up clinical trials are needed to confirm the long-term conclusions regarding the use of sitagliptin and metformin in combination 6.
• The TECOS CV safety trial found that sitagliptin was noninferior to placebo in terms of the risk of major adverse cardiac events in patients with type 2 diabetes and established cardiovascular disease 7.