Sitagliptin/Metformin Extended-Release Tablets (Janumet XR) is a fixed-dose combination oral antihyperglycemic medication. It combines sitagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, with metformin extended-release, a biguanide antihyperglycemic agent, and is indicated as an adjunctive therapy for glycemic control in adult patients with type 2 diabetes mellitus.
Dosage and Administration, Recommended Dosage of Sitagliptin/Metformin Extended-Release Tablets (Janumet XR)
Administration Method
Sitagliptin/Metformin Extended-Release Tablets should be taken once daily with a meal.
If two tablets are required for the daily dose, both should be taken at the same meal. The tablets must not be split, crushed, or chewed.
Recommended Dosage
For patients not previously treated with metformin, the recommended starting dose is 100 mg sitagliptin combined with 1000 mg metformin extended-release. Dose escalation is advised gradually to minimize the gastrointestinal adverse reactions associated with metformin.
For patients already receiving metformin therapy, the starting dose should include 100 mg sitagliptin plus the patient’s current daily dose of metformin.
For patients previously taking metformin immediate-release 850 mg twice daily or 1000 mg twice daily, the recommended starting dose is two tablets of 50 mg sitagliptin/1000 mg metformin extended-release, taken together.
Dose Adjustment of Sitagliptin/Metformin Extended-Release Tablets (Janumet XR)
Renal Function Assessment and Adjustment
Renal function (estimated glomerular filtration rate, eGFR) must be assessed prior to the initiation of treatment and periodically thereafter.
Use of this medication is contraindicated in patients with eGFR < 30 mL/min/1.73 m². Treatment must be discontinued immediately if eGFR falls to this level during therapy.
Initiation of treatment is not recommended in patients with eGFR between 30–45 mL/min/1.73 m².
When eGFR < 45 mL/min/1.73 m², the benefits and risks of continued treatment should be evaluated, and the dose of sitagliptin should be restricted to 50 mg once daily.
Temporary Discontinuation for Iodinated Contrast Media Procedures
This recommendation applies to patients with eGFR 30–60 mL/min/1.73 m², as well as patients with a history of liver disease, alcoholism, heart failure, and those undergoing intravascular administration of iodinated contrast media.
The medication must be withheld at the time of, or prior to, the procedure. Renal function should be re-evaluated 48 hours after the procedure, and treatment may be resumed only if renal function remains stable.
Use in Special Populations of Sitagliptin/Metformin Extended-Release Tablets (Janumet XR)
Geriatric Patients
Geriatric patients (≥ 65 years of age) are at increased risk of impaired hepatic/renal function and lactic acidosis.
More frequent monitoring of renal function is required, and treatment should generally be initiated at the lower end of the dosage range.
Patients with Hepatic Impairment
Use of Sitagliptin/Metformin Extended-Release Tablets should be avoided in patients with liver disease, as hepatic impairment can compromise lactate clearance capacity.
The medication is contraindicated in patients with clinical or laboratory evidence of liver disease.
Pregnant and Lactating Women
Adequate data on the use of Sitagliptin/Metformin Extended-Release Tablets in pregnant women are lacking. For the management of gestational diabetes, the maternal and fetal risks must be carefully weighed.
Caution is advised when using this medication during lactation. Sitagliptin is excreted in the milk of lactating rats, and limited data are available regarding the presence of metformin in human milk and its effects on infants. The necessity of treatment should be comprehensively evaluated.
