JANUMET XR Sitagliptin Phosphate / Metformin Hydrochloride 100mg / 1g Extended Release Film-Coated Tablet 1's

SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) is indicated as initial therapy in patients with type 2 diabetes mellitus to improve glycemic control when diet and exercise do not provide adequate glycemic control.
SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) is indicated as an adjunct to diet and exercise to improve glycemic control in patients with type 2 diabetes mellitus inadequately controlled on metformin or sitagliptin alone or in patients already being treated with the combination of sitagliptin and metformin.
SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) is indicated as part of triple combination therapy with a sulfonylurea as an adjunct to diet and exercise in patients with type 2 diabetes mellitus inadequately controlled with any two of the three agents: Metformin, sitagliptin, or a sulfonylurea.
SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) is indicated as part of triple combination therapy with a PPARγ agonist (i.e., thiazolidinediones) as an adjunct to diet and exercise in patients with type 2 diabetes mellitus inadequately controlled with any two of the three agents: Metformin, sitagliptin, or a PPARγ agonist.
SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) is indicated in patients with type 2 diabetes mellitus as an adjunct to diet and exercise to improve glycemic control in combination with insulin.

General: The dosage of antihyperglycemic therapy with SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) should be individualized on the basis of the patient's current regimen, effectiveness, and tolerability while not exceeding the maximum recommended daily dose of 100 mg sitagliptin.
SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) should be given once daily with a meal preferably in the evening. The dose should be escalated gradually to reduce the gastrointestinal (GI) side effects due to metformin. Additionally, administration of SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) with food enhances plasma concentrations of metformin. To preserve the modified-release properties, the tablets must not be split, broken, crushed, or chewed before swallowing. There have been reports of incompletely dissolved SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) tablets being eliminated in the feces. It is not known whether this material seen in feces contains active drug. If a patient reports repeatedly seeing tablets in feces, the healthcare provider should assess adequacy of glycemic control.
Dosing Recommendations: The starting dose of SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) should be based on the patient's current regimen.
SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) should be given once daily with a meal preferably in the evening. SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) tablet is available in 100 mg sitagliptin/1 g extended-release metformin hydrochloride strength.
The 100 mg sitagliptin/1 g metformin hydrochloride extended-release tablet should be taken as a single tablet once daily.
As Initial Therapy: For patients with type 2 diabetes mellitus, whose hyperglycemia is inadequately controlled with diet and exercise alone, the recommended total daily starting dose of JANUMET or SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) is 100 mg sitagliptin and 1 g metformin hydrochloride. Patients with inadequate glycemic control on this dose can be titrated gradually to reduce gastrointestinal side effects associated with metformin, up to the maximum recommended daily metformin dose of 2000 mg.
For patients inadequately controlled on metformin monotherapy: For patients inadequately controlled on metformin alone, the recommended total daily starting dose of SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) is 100 mg sitagliptin and the previously prescribed dose of metformin.
For patients inadequately controlled on sitagliptin monotherapy: For patients inadequately controlled on sitagliptin alone, the recommended starting dose of SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) is 100 mg sitagliptin and 1 g metformin hydrochloride. The metformin dose can be titrated as needed to achieve glycemic control. Gradual dose escalation to reduce the gastrointestinal (GI) side effects associated with metformin should be considered. Patients taking sitagliptin monotherapy dose-adjusted for renal insufficiency should not be switched to SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) (see Contraindications).
For patients switching from coadministration of sitagliptin and metformin: For patients switching from coadministration of sitagliptin and metformin, SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) may be initiated at the previously prescribed dose of sitagliptin and metformin.
For patients inadequately controlled on dual combination therapy with any two of the following three antihyperglycemic agents:Sitagliptin, metformin or a sulfonylurea: The usual starting dose of SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) should provide 100 mg total daily dose of sitagliptin. In determining the starting dose of the metformin component, the patient's level of glycemic control and current dose (if any) of metformin should be considered. Gradual dose escalation to reduce the gastrointestinal (GI) side effects associated with metformin should be considered. Patients currently on or initiating a sulfonylurea may require lower sulfonylurea doses to reduce the risk of sulfonylurea-induced hypoglycemia (see Precautions).
For patients inadequately controlled on dual combination therapy with any two of the following three antihyperglycemic agents: Sitagliptin, metformin or a PPARγ agonist (i.e. thiazolidinediones):The usual starting dose of SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) should provide 100 mg total daily dose of sitagliptin. In determining the starting dose of the metformin component, the patient's level of glycemic control and current dose (if any) of metformin should be considered. Gradual dose escalation to reduce the gastrointestinal (GI) side effects associated with metformin should be considered.
For patients inadequately controlled on dual combination therapy with any two of the following three antihyperglycemic agents: Sitagliptin, metformin or insulin: The usual starting dose of SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) should provide 100 mg total daily dose of sitagliptin. In determining the starting dose of the metformin component, the patient's level of glycemic control and current dose (if any) of metformin should be considered. Gradual dose escalation to reduce the gastrointestinal (GI) side effects associated with metformin should be considered. Patients currently on or initiating insulin therapy may require lower doses of insulin to reduce the risk of hypoglycemia (see Precautions).
No studies have been performed specifically examining the safety and efficacy of SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) in patients previously treated with other oral antihyperglycemic agents and switched to SITAGLIPTINPHOSPHATE + METFORMIN HCl (JANUMET XR). Any change in therapy of type 2 diabetes should be undertaken with care and appropriate monitoring as changes in glycemic control can occur.
Recommendations for use in renal impairment: Assess renal function prior to initiation of SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) and periodically thereafter.
SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) is contraindicated in patients with an estimated glomerular filtration rate (eGFR) <30 mL/min/1.73 m². Discontinue SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) if the patient's eGFR later falls below 30 mL/min/1.73 m² (see Contraindications and Precautions).
SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR): Initiation of SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) in patients with an eGFR ≥30 mL/min/1.73 m² and <45 mL/min/1.73 m² is not recommended. In patients taking SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) whose eGFR later falls below 45 mL/min/1.73 m², assess the benefit and risk of continuing therapy and limit dose of the sitagliptin component to 50 mg once day.
Discontinuation for iodinated contrast imaging procedures: Discontinue SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) at the time of, or prior to, an iodinated contrast imaging procedure; in patients with an eGFR ≥30 to <60 mL/min/1.73 m²; in patients with history of liver disease, alcoholism or heart failure; or in patients who will be administered intra-arterial iodinated contrast. Re-evaluate eGFR 48 hours after the imaging procedure; restart SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) if renal function is acceptable (see Precautions).

Should be taken with food: Take w/ meals preferably in the evening. Swallow whole, do not split/break/crush/chew.

SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) is contraindicated in patients with: Severe renal impairment (eGFR <30 mL/min/1.73 m²) (see Metformin hydrochloride: Renal Impairment under Precautions).
Known hypersensitivity to sitagliptin phosphate, metformin hydrochloride or any other component of SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) (see Sitagliptin phosphate: Hypersensitivity Reactions under Precautions and Postmarketing Experience under Side Effects).
Acute or chronic metabolic acidosis, including diabetic ketoacidosis, with or without coma.
SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) should be temporarily discontinued in patients undergoing radiologic studies involving intravascular administration of iodinated contrast materials, because the use of such products may result in acute alteration of renal function (see Metformin hydrochloride under Precautions).

SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR): SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) should not be used in patients with type 1 diabetes or for the treatment of diabetic ketoacidosis.
Pancreatitis: In postmarketing experience there have been reports of acute pancreatitis, including fatal and non-fatal hemorrhagic or necrotizing pancreatitis (see Postmarketing Experience under Side Effects), in patients taking sitagliptin. Because these reports are made voluntarily from a population of uncertain size, it is generally not possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Patients should be informed of the characteristic symptom of acute pancreatitis: persistent, severe abdominal pain. Resolution of pancreatitis has been observed after discontinuation of sitagliptin. If pancreatitis is suspected, SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR), and other potentially suspect medicinal products, should be discontinued.
Monitoring of renal function: Metformin and sitagliptin are known to be substantially excreted by the kidney. The risk of metformin accumulation and lactic acidosis increases with the degree of impairment of renal function. SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) is contraindicated in severe renal impairment, patients with an eGFR <30 mL/min/1.73 m² (see Dosage & Administration, Contraindication and Metformin hydrochloride: Lactic acidosis under Precautions).
Before initiation of therapy with SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) and at least annually thereafter, renal function should be assessed. In patients in whom development of renal dysfunction is anticipated, renal function should be assessed more frequently and SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) discontinued if evidence of renal impairment is present.
Hypoglycemia in Combination with a Sulfonylurea or with Insulin: As is typical with other antihyperglycemic agents, hypoglycemia has been observed when sitagliptin and metformin were used in combination with insulin or a sulfonylurea (see Side Effects). Therefore, to reduce the risk of sulfonylurea- or insulin-induced hypoglycemia, a lower dose of sulfonylurea or insulin may be considered (see Dosage & Administration).
Sitagliptin phosphate: Hypoglycemia in Combination with a Sulfonylurea or with Insulin: In clinical trials of sitagliptin as monotherapy and as part of combination therapy with agents not known to cause hypoglycemia (i.e., metformin or a PPARγ agonist (thiazolidinedione), rates of hypoglycemia reported with sitagliptin were similar to rates in patients taking placebo. As typical with other antihyperglycemic agents, hypoglycemia has been observed when sitagliptin was used in combination with insulin or a sulfonylurea (see Side Effects).
Therefore, to reduce the risk of sulfonylurea- or insulin-induced hypoglycemia, a lower dose of sulfonylurea or insulin may be considered (see Dosage & Administration).
Hypersensitivity Reactions: There have been postmarketing reports of serious hypersensitivity reactions in patients treated with sitagliptin, one of the components of SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR). These reactions include anaphylaxis, angioedema, and exfoliative skin conditions including Stevens-Johnson syndrome. Because these reactions are reported voluntarily from a population of uncertain size, it is generally not possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Onset of these reactions occurred within the first 3 months after initiation of treatment with sitagliptin, with some reports occurring after the first dose. If a hypersensitivity reaction is suspected, discontinue SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR), assess for other potential causes for the event, and institute alternative treatment for diabetes (see Contraindications and Postmarketing Experience under Side Effects).
Bullous Pemphigoid: Postmarketing cases of bullous pemphigoid requiring hospitalization have been reported with DPP-4 inhibitor use. In reported cases, patients typically recovered with topical or systemic immunosuppressive treatment and discontinuation of the DPP-4 inhibitor. Tell patients to report development of blisters or erosions while receiving SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR). If bullous pemphigoid is suspected, SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) should be discontinued and referral to a dermatologist should be considered for diagnosis and appropriate treatment.
Metformin hydrochloride:Lactic Acidosis: Lactic acidosis is a rare, but serious, metabolic complication that can occur due to metformin accumulation during treatment with SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR); when it occurs, it is fatal in approximately 50% of cases.
Lactic acidosis may also occur in association with a number of pathophysiologic conditions, including diabetes mellitus, and whenever there is significant tissue hypoperfusion and hypoxemia. Lactic acidosis is characterized by elevated blood lactate levels (>5 mmol/L), decreased blood pH, electrolyte disturbances with an increased anion gap, and an increased lactate/pyruvate ratio. When metformin is implicated as the cause of lactic acidosis, metformin plasma levels >5 μg/mL are generally found.
The reported incidence of lactic acidosis in patients receiving metformin hydrochloride is very low (approximately 0.03 cases/1000 patient-years, with approximately 0.015 fatal cases/1000 patient-years). In more than 20,000 patient-years exposure to metformin in clinical trials, there were no reports of lactic acidosis. Reported cases have occurred primarily in diabetic patients with significant renal insufficiency, including both intrinsic renal disease and renal hypoperfusion, often in the setting of multiple concomitant medical/surgical problems and multiple concomitant medications (see Recommendations for use in renal impairment under Dosage & Administration). Patients with congestive heart failure requiring pharmacologic management, in particular those with unstable or acute congestive heart failure who are at risk of hypoperfusion and hypoxemia, are at increased risk of lactic acidosis. The risk of lactic acidosis increases with the degree of renal dysfunction and the patient's age. The risk of lactic acidosis may, therefore, be significantly decreased by regular monitoring of renal function in patients taking metformin and by use of the minimum effective dose of metformin. In particular, treatment of the elderly should be accompanied by careful monitoring of renal function (see Use in Elderly: Metformin hydrochloride as follows). In addition, metformin should be promptly withheld in the presence of any condition associated with hypoxemia, dehydration, or sepsis. Because impaired hepatic function may significantly limit the ability to clear lactate, metformin should generally be avoided in patients with clinical or laboratory evidence of hepatic disease. Patients should be cautioned against excessive alcohol intake, either acute or chronic, when taking metformin, since alcohol potentiates the effects of metformin hydrochloride on lactate metabolism. In addition, metformin should be temporarily discontinued prior to any intravascular radiocontrast study and for any surgical procedure.
The onset of lactic acidosis often is subtle, and accompanied only by nonspecific symptoms such as malaise, myalgias, respiratory distress, increasing somnolence, and nonspecific abdominal distress. There may be associated hypothermia, hypotension, and resistant bradyarrhythmias with more marked acidosis. The patient and the patient's physician must be aware of the possible importance of such symptoms and the patient should be instructed to notify the physician immediately if they occur. Metformin should be withdrawn until the situation is clarified. Serum electrolytes, ketones, blood glucose, and if indicated, blood pH, lactate levels, and even blood metformin levels may be useful. Once a patient is stabilized on any dose level of metformin, gastrointestinal symptoms, which are common during initiation of therapy, are unlikely to be drug related. Later occurrence of gastrointestinal symptoms could be due to lactic acidosis or other serious disease.
Levels of fasting venous plasma lactate above the upper limit of normal but less than 5 mmol/L in patients taking metformin do not necessarily indicate impending lactic acidosis and may be explainable by other mechanisms, such as poorly controlled diabetes or obesity, vigorous physical activity, or technical problems in sample handling.
Lactic acidosis should be suspected in any diabetic patient with metabolic acidosis lacking evidence of ketoacidosis (ketonuria and ketonemia).
Lactic acidosis is a medical emergency that must be treated in a hospital setting. In a patient with lactic acidosis who is taking metformin, the drug should be discontinued immediately and general supportive measures promptly instituted. Because metformin hydrochloride is dialyzable (with a clearance of up to 170 mL/min under good hemodynamic conditions), prompt hemodialysis is recommended to correct the acidosis and remove the accumulated metformin. Such management often results in prompt reversal of symptoms and recovery (see Contraindications).
Hypoglycemia: Hypoglycemia does not occur in patients receiving metformin alone under usual circumstances of use, but could occur when caloric intake is deficient, when strenuous exercise is not compensated by caloric supplementation, or during concomitant use with other glucose-lowering agents (such as sulfonylureas and insulin) or ethanol. Elderly, debilitated, or malnourished patients, and those with adrenal or pituitary insufficiency or alcohol intoxication are particularly susceptible to hypoglycemic effects. Hypoglycemia may be difficult to recognize in the elderly, and in people who are taking β-adrenergic blocking drugs.
Use of concomitant medications that may affect renal function or metformin disposition: Concomitant medication(s) that may affect renal function or result in significant hemodynamic change or may interfere with the disposition of metformin, such as cationic drugs that are eliminated by renal tubular secretion (see Metformin hydrochloride under Interactions), should be used with caution.
Radiologic studies involving the use of intravascular iodinated contrast materials (for example, intravenous urogram, intravenous cholangiography, angiography, and computed tomography (CT) Scans with intravascular contrast materials): Intravascular contrast studies with iodinated materials can lead to acute alteration of renal function and have been associated with lactic acidosis in patients receiving metformin (see Contraindications). Therefore, in patients with an eGFR ≥30 to <60 mL/min/1.73 m², in patients with a history of hepatic impairment, alcoholism, or heart failure, or in patients who will be administered intra-arterial iodinated contrast, SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) should be temporarily discontinued at the time of or prior to the procedure, and withheld for 48 hours subsequent to the procedure and reinstituted only after renal function has been re-evaluated and found to be acceptable (see Dosage & Administration).
Hypoxic states: Cardiovascular collapse (shock) from whatever cause, acute congestive heart failure, acute myocardial infarction and other conditions characterized by hypoxemia have been associated with lactic acidosis and may also cause prerenal azotemia. When such events occur in patients on SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) therapy, the drug should be promptly discontinued.
Surgical procedures: Use of SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) should be temporarily suspended for any surgical procedure (except minor procedures not associated with restricted intake of food and fluids) and should not be restarted until the patient's oral intake has resumed and renal function has been evaluated as acceptable (see Dosage & Administration).
Alcohol intake: Alcohol is known to potentiate the effect of metformin on lactate metabolism. Patients, therefore, should be warned against excessive alcohol intake, acute or chronic, while receiving SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR).
Impaired hepatic function: Since impaired hepatic function has been associated with some cases of lactic acidosis, SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) should generally be avoided in patients with clinical or laboratory evidence of hepatic disease.
Vitamin B₁₂ levels: In controlled clinical trials of metformin of 29 weeks duration, a decrease to subnormal levels of previously normal serum Vitamin B₁₂ levels, without clinical manifestations, was observed in approximately 7% of patients. Such decrease, possibly due to interference with B₁₂ absorption from the B₁₂-intrinsic factor complex, is, however, very rarely associated with anemia and appears to be rapidly reversible with discontinuation of metformin or Vitamin B₁₂ supplementation. Measurement of hematologic parameters on an annual basis is advised in patients on SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) and any apparent abnormalities should be appropriately investigated and managed.
Certain individuals (those with inadequate Vitamin B₁₂ or calcium intake or absorption) appear to be predisposed to developing subnormal Vitamin B₁₂ levels. In these patients, routine serum Vitamin B₁₂ measurements at two- to three-year intervals may be useful.
Change in clinical status of patients with previously controlled type 2 diabetes: A patient with type 2 diabetes previously well controlled on SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) who develops laboratory abnormalities or clinical illness (especially vague and poorly defined illness) should be evaluated promptly for evidence of ketoacidosis or lactic acidosis. Evaluation should include serum electrolytes and ketones, blood glucose and, if indicated, blood pH, lactate, pyruvate, and metformin levels. If acidosis of either form occurs, SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) must be stopped immediately and other appropriate corrective measures initiated.
Loss of control of blood glucose: When a patient stabilized on any diabetic regimen is exposed to stress such as fever, trauma, infection, or surgery, a temporary loss of glycemic control may occur. At such times, it may be necessary to withhold SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) and temporarily administer insulin. SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) may be reinstituted after the acute episode is resolved.
Use in Children: Safety and effectiveness of SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) in pediatric patients under 18 years have not been established.
Use in Elderly: Because sitagliptin and metformin are substantially excreted by the kidney and because aging can be associated with reduced renal function, SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) should be used with caution as age increases. Care should be taken in dose selection and should be based on careful and regular monitoring of renal function (see Monitoring of renal function previously).
Sitagliptin phosphate: In clinical studies, the safety and effectiveness of sitagliptin in the elderly (≥65 years) were comparable to those seen in younger patients (<65 years).
Metformin hydrochloride: Controlled clinical studies of metformin did not include sufficient numbers of elderly patients to determine whether they respond differently from younger patients, although other reported clinical experience has not identified differences in responses between the elderly and younger patients.

Diarrhea, nausea, dyspepsia, flatulence, vomiting, headache, hypoglycemia, abdominal pain.

Sitagliptin and metformin: Coadministration of multiple doses of sitagliptin (50 mg b.i.d.) and metformin (1000 mg b.i.d.) did not meaningfully alter the pharmacokinetics of either sitagliptin or metformin in patients with type 2 diabetes.
Pharmacokinetic drug interaction studies with SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) have not been performed; however, such studies have been conducted with the individual components of SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR), sitagliptin and metformin.
Sitagliptin phosphate: In drug interaction studies, sitagliptin did not have clinically meaningful effects on the pharmacokinetics of the following: metformin, rosiglitazone, glyburide, simvastatin, warfarin, and oral contraceptives. Based on these data, sitagliptin does not inhibit CYP isozymes CYP3A4, 2C8, or 2C9. Based on in vitro data, sitagliptin is also not expected to inhibit CYP2D6, 1A2, 2C19 or 2B6 or to induce CYP3A4.
Population pharmacokinetic analyses have been conducted in patients with type 2 diabetes. Concomitant medications did not have a clinically meaningful effect on sitagliptin pharmacokinetics. Medications assessed were those that are commonly administered to patients with type 2 diabetes including cholesterol-lowering agents (e.g., statins, fibrates, ezetimibe), anti-platelet agents (e.g., clopidogrel), antihypertensives (e.g., ACE inhibitors, angiotensin receptor blockers, beta-blockers, calcium channel blockers, hydrochlorothiazide), analgesics and non-steroidal anti-inflammatory agents (e.g., naproxen, diclofenac, celecoxib), anti-depressants (e.g., bupropion, fluoxetine, sertraline), antihistamines (e.g., cetirizine), proton-pump inhibitors (e.g., omeprazole, lansoprazole), and medications for erectile dysfunction (e.g., sildenafil).
There was a slight increase in the area under the curve (AUC, 11%) and mean peak drug concentration (C_max, 18%) of digoxin with the coadministration of sitagliptin. These increases are not considered to be clinically meaningful. Patients receiving digoxin should be monitored appropriately. The AUC and C_max of sitagliptin were increased approximately 29% and 68%, respectively, in subjects with coadministration of a single 100-mg oral dose of JANUVIA and a single 600-mg oral dose of cyclosporine, a potent probe inhibitor of p-glycoprotein. The observed changes in sitagliptin pharmacokinetics are not considered to be clinically meaningful.
Metformin hydrochloride: Glyburide: In a single-dose interaction study in type 2 diabetes patients, co-administration of metformin and glyburide did not result in any changes in either metformin pharmacokinetics or pharmacodynamics. Decreases in glyburide AUC and C_max were observed, but were highly variable. The single-dose nature of this study and the lack of correlation between glyburide blood levels and pharmacodynamic effects make the clinical significance of this interaction uncertain.
Furosemide: A single-dose, metformin-furosemide drug interaction study in healthy subjects demonstrated that pharmacokinetic parameters of both compounds were affected by coadministration. Furosemide increased the metformin plasma and blood C_max by 22% and blood AUC by 15%, without any significant change in metformin renal clearance. When administered with metformin, the C_max and AUC of furosemide were 31% and 12% smaller, respectively, than when administered alone, and the terminal half-life was decreased by 32%, without any significant change in furosemide renal clearance. No information is available about the interaction of metformin and furosemide when coadministered chronically.
Nifedipine: A single-dose, metformin-nifedipine drug interaction study in normal healthy volunteers demonstrated that coadministration of nifedipine increased plasma metformin C_max and AUC by 20% and 9%, respectively, and increased the amount excreted in the urine. T_max and half-life were unaffected. Nifedipine appears to enhance the absorption of metformin. Metformin had minimal effects on nifedipine.
Drugs that reduce metformin clearance: Concomitant use of drugs that interfere with common renal tubular transport systems involved in the renal elimination of metformin (e.g., organic cationic transporter-2 [OCT2] / multidrug and toxin extrusion [MATE] inhibitors such as ranolazine, vandetanib, dolutegravir, and cimetidine) could increase systemic exposure to metformin and may increase the risk for lactic acidosis. Consider the benefits and risks of concomitant use.
Other: Certain drugs tend to produce hyperglycemia and may lead to loss of glycemic control. These drugs include the thiazides and other diuretics, corticosteroids, phenothiazines, thyroid products, estrogens, oral contraceptives, phenytoin, nicotinic acid, sympathomimetics, calcium channel blocking drugs, and isoniazid. When such drugs are administered to a patient receiving SITAGLIPTIN PHOSPHATE + METFORMIN HCl (JANUMET XR) the patient should be closely observed to maintain adequate glycemic control.
In healthy volunteers, the pharmacokinetics of metformin and propranolol, and metformin and ibuprofen were not affected when coadministered in single-dose interaction studies.
Metformin is negligibly bound to plasma proteins and is, therefore, less likely to interact with highly protein-bound drugs such as salicylates, sulfonamides, chloramphenicol, and probenecid, as compared to the sulfonylureas, which are extensively bound to serum proteins.

Antidiabetic Agents