Janumet combines sitagliptin with metformin for adults with type 2 diabetes. The metformin component adds kidney precautions and a boxed warning about lactic acidosis.
The approved uses and formulations described here follow US prescribing information. They may differ in other countries.
| Medicine detail | Details |
|---|---|
| Active ingredient(s) | sitagliptin / metformin hydrochloride |
| Medicine class | DPP-4 inhibitor / biguanide combination |
| Forms and strengths | Immediate-release tablets: 50/500 and 50/1000 mg; Janumet XR is a separate formulation |
Two ingredients with different effects
Sitagliptin is a DPP-4 inhibitor; metformin reduces glucose production by the liver and has other effects on glucose handling. Janumet is used alongside diet and exercise in adults with type 2 diabetes. Janumet contains immediate-release metformin; Janumet XR contains an extended-release formulation and has different instructions.
Source: [1]
Understanding the tablet strength
Janumet tablets contain 50 mg of sitagliptin with either 500 or 1,000 mg of metformin. In a strength such as 50/1,000 mg, the first number is sitagliptin and the second is metformin. Follow the prescribed schedule with meals; Janumet XR has its own dosing instructions.
Source: [1]
Lactic acidosis and kidney function
Janumet carries a boxed warning for metformin-associated lactic acidosis. It must not be used with severe kidney impairment. It is also unsuitable for some people with moderately reduced kidney function because its fixed sitagliptin dose cannot be lowered enough. The clinician checks kidney function and provides any instructions needed around contrast scans or other procedures.
Source: [1]
Other precautions
Pancreatitis, serious hypersensitivity, severe joint pain and bullous pemphigoid are among the warnings relevant to sitagliptin-containing treatment. Gastrointestinal effects can occur with metformin. Report persistent severe abdominal pain, significant skin blistering or other concerning symptoms rather than attributing everything to routine stomach upset.
Source: [1]
Checking for duplicate ingredients
Januvia contains sitagliptin alone, and metformin is also available separately. When Janumet is prescribed, ask which existing tablets it replaces. Taking the combination alongside either ingredient could duplicate treatment.
Source: [1]
Questions and answers
Does Janumet contain Januvia’s ingredient?
Yes. It contains sitagliptin plus metformin.
Is Janumet XR the same release formulation?
No. Janumet XR contains extended-release metformin and has different dosing instructions from immediate-release Janumet.
Why is kidney function important?
Both the metformin safety restrictions and the suitability of the fixed sitagliptin dose depend on kidney function.
Related reading
Sources
Sources checked 1 October 2026. This information does not replace advice from your healthcare professional. For complete warnings and instructions, read the product information and consult the prescribing team.
Reviewed by: Mattias Hagman, PhD
About the reviewer:
Dr Mattias Hagman (PhD, University of Sydney) has an academic background and experience working with healthcare-related content and regulated industries. He has lecturing experience at international universities, including Stockholm University and the University of Malta.
Last reviewed: October 2026