Pharmacologic class:

Antihyperglycemic (dipeptidyl peptidase-4 inhibitor [DPP-4] + biguanide)

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Active ingredients:

Sitagliptin 50 mg, metformin (as HCl) 500 mg; tabs.


Janumet 50 mg/1000 mg

Active ingredients:

Sitagliptin 50 mg, metformin (as HCl) 1000 mg; tabs.


Adjunct to diet and exercise to improve glycemic control in patients with type 2 diabetes who are not adequately controlled on metformin or sitagliptin alone or in patients already being treated with the combination of sitagliptin and metformin.


Janumet combines the two antihyperglycemic agents sitagliptin and metformin. Sitagliptin, a DPP-4 inhibitor, increases and prolongs the activity of incretins, hormones that play a role in the regulation of glucose homeostasis. Metformin, a biguanide, reduces endogenous hepatic glucose production, decreases intestinal absorption of glucose, and improves insulin sensitivity by increasing peripheral glucose uptake and utilization.

Clinical trials:

There have been no clinical efficacy studies conducted with Janumet; however, bioequivalence of Janumet with co-administered sitagliptin and metformin tablets was demonstrated.


Individualize. Take twice daily with meals. Previously on metformin alone: initially 50 mg twice daily of sitagliptin plus metformin dose. Previously on metformin 850 mg twice daily: start with 50 mg/1000 mg twice daily. Previously on sitagliptin alone: initially 50 mg/500 mg twice daily; may increase to 50 mg/1000 mg twice daily. Previously on sitagliptin and metformin: switch on a mg/mg basis. Max 100 mg sitagliptin/2000 mg metformin per day.


<18 years: not recommended.


Renal disease or dysfunction. Metabolic acidosis, ketoacidosis. Concomitant intravascular iodinated contrast agents (suspend during and for 48 hours after use). Type 1 diabetes.


Confirm normal renal function before starting and monitor (esp. in elderly). Avoid if clinical or lab evidence of hepatic disease. Discontinue if lactic acidosis, ketoacidosis, renal impairment, shock, acute MI, acute congestive heart failure, sepsis, or hypoxemia occurs. May need to suspend therapy during periods of stress or if dehydration occurs or before surgery.

Monitor hematology (esp. serum vitamin B12 in susceptible patients). Elderly, debilitated, malnourished, deficient caloric intake, adrenal or pituitary insufficiency, or alcohol intoxication: increased risk of hypoglycemia. Pregnancy (Cat. B). Nursing mothers.


Cationic drugs eliminated by renal tubular secretion (e.g., amiloride, digoxin, morphine, procainamide, quinine, quinidine, ranitidine, triamterene, trimethoprim, vancomycin), furosemide, nifedipine, cimetidine: may increase metformin levels. Avoid excessive alcohol intake (potentiates effects of metformin on lactate). Monitor digoxin. Diuretics, steroids, estrogens, oral contraceptives, phenothiazines, phenytoin, thyroid products, nicotinic acid, sympathomimetics, calcium channel blockers, isoniazid, others that may cause hyperglycemia. Beta blockers may mask hypoglycemia.

Adverse reactions:

Nasopharyngitis, GI disturbances, asthenia, headache; lactic acidosis (rare, half of the cases are fatal).

How supplied:

Tabs—60, 180, 1000.

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