WARNING: LACTIC ACIDOSIS
Postmarketing cases of metformin-associated lactic acidosis have resulted in death, hypothermia, hypotension, and resistant bradyarrhythmias. The onset of metformin-associated lactic acidosis is often subtle, accompanied only by nonspecific symptoms such as malaise, myalgias, respiratory distress, somnolence, and abdominal pain. Metformin-associated lactic acidosis was characterized by elevated blood lactate levels (>5 mmol/Liter), anion gap acidosis (without evidence of ketonuria or ketonemia), an increased lactate/pyruvate ratio, and metformin plasma levels generally >5 mcg/mL.
Risk factors for metformin-associated lactic acidosis include renal impairment, concomitant use of certain drugs (eg, carbonic anhydrase inhibitors such as topiramate), age 65 years old or greater, having a radiological study with contrast, surgery and other procedures, hypoxic states (eg, acute congestive heart failure), excessive alcohol intake, and hepatic impairment.
If metformin-associated lactic acidosis is suspected, immediately discontinue JANUMET or JANUMET XR and institute general supportive measures in a hospital setting. Prompt hemodialysis is recommended.
JANUMET and JANUMET XR are contraindicated in patients with severe renal impairment (estimated glomerular filtration rate [eGFR] below 30 mL/min/1.73 m2); acute or chronic metabolic acidosis, including diabetic ketoacidosis; or history of a serious hypersensitivity reaction to JANUMET, JANUMET XR, sitagliptin, or metformin, such as anaphylaxis or angioedema.
Postmarketing metformin-associated lactic acidosis cases primarily occurred in patients with significant renal impairment. The risk of metformin accumulation and metformin-associated lactic acidosis increases with the severity of renal impairment because metformin is substantially excreted by the kidney.
JANUMET: Before initiating JANUMET, obtain an eGFR. JANUMET is contraindicated in patients with an eGFR below 30 mL/min/1.73 m2. JANUMET is not recommended in patients with an eGFR between 30 and <45 mL/min/1.73 m2 because these patients require a lower dosage of sitagliptin than what is available in the fixed combination product of JANUMET. Obtain an eGFR at least annually in all patients taking JANUMET. In patients at increased risk for the development of renal impairment (eg, the elderly), renal function should be assessed more frequently.
JANUMET XR: Before initiating JANUMET XR, obtain an eGFR. JANUMET XR is contraindicated in patients with an eGFR less than 30 mL/min/1.73 m2. Discontinue JANUMET XR if the patient’s eGFR later falls below 30 mL/min/1.73 m2. Initiation of JANUMET XR is not recommended in patients with an eGFR between 30 and 45 mL/min/1.73 m2. In patients taking JANUMET XR whose eGFR later falls below 45 mL/min/1.73 m2, assess the benefit and risk of continuing therapy. Obtain an eGFR at least annually in all patients taking JANUMET XR. In patients at increased risk for the development of renal impairment (eg, the elderly), renal function should be assessed more frequently.
The concomitant use of JANUMET or JANUMET XR with specific drugs may increase the risk of metformin-associated lactic acidosis: those that impair renal function, result in significant hemodynamic change, interfere with acid-base balance, or increase metformin accumulation. Consider more frequent monitoring of patients.
The risk of metformin-associated lactic acidosis increases with the patient’s age because elderly patients have a greater likelihood of having hepatic, renal, or cardiac impairment than younger patients. Assess renal function more frequently in elderly patients.
Administration of intravascular iodinated contrast agents in metformin-treated patients has led to an acute decrease in renal function and the occurrence of lactic acidosis. Stop JANUMET or JANUMET XR at the time of, or prior to, an iodinated contrast imaging procedure in patients with an eGFR between 30 and 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. Re-evaluate eGFR 48 hours after the imaging procedure; restart JANUMET or JANUMET XR if renal function is stable.
Withholding of food and fluids during surgical or other procedures may increase the risk for volume depletion, hypotension, and renal impairment. JANUMET or JANUMET XR should be temporarily discontinued while patients have restricted food and fluid intake.
Postmarketing cases of metformin-associated lactic acidosis have occurred in the setting of acute congestive heart failure (particularly when accompanied by hypoperfusion and hypoxemia). Cardiovascular collapse (shock), acute myocardial infarction, sepsis, and other conditions associated with hypoxemia have been associated with lactic acidosis and may also cause prerenal azotemia. Discontinue JANUMET or JANUMET XR if this occurs.
Alcohol potentiates the effect of metformin on lactate metabolism and this may increase the risk of metformin-associated lactic acidosis. Warn patients against excessive alcohol intake while receiving JANUMET or JANUMET XR.
Patients with hepatic impairment have developed metformin-associated lactic acidosis. This may be due to impaired lactate clearance resulting in higher lactate blood levels. Avoid using JANUMET or JANUMET XR in patients with clinical or laboratory evidence of hepatic disease.
There have been postmarketing reports of acute pancreatitis, including fatal and nonfatal hemorrhagic or necrotizing pancreatitis, in patients taking sitagliptin with or without metformin. After initiating JANUMET or JANUMET XR, observe patients carefully for signs and symptoms of pancreatitis. If pancreatitis is suspected, promptly discontinue JANUMET or JANUMET XR and initiate appropriate management. It is unknown whether patients with a history of pancreatitis are at increased risk of developing pancreatitis while taking JANUMET or JANUMET XR.
An association between dipeptidyl peptidase-4 (DPP-4) inhibitor treatment and heart failure has been observed in cardiovascular outcomes trials for two other members of the DPP-4 inhibitor class. These trials evaluated patients with type 2 diabetes mellitus and atherosclerotic cardiovascular disease. Consider the risks and benefits of JANUMET or JANUMET XR prior to initiating treatment in patients at risk for heart failure, such as those with a prior history of heart failure and a history of renal impairment, and observe these patients for signs and symptoms of heart failure during therapy. Advise patients of the characteristic symptoms of heart failure and to immediately report such symptoms. If heart failure develops, evaluate and manage according to current standards of care and consider discontinuation of JANUMET or JANUMET XR.
There have been postmarketing reports of worsening renal function in patients taking sitagliptin with or without metformin, including acute renal failure, sometimes requiring dialysis. Before initiating JANUMET or JANUMET XR and at least annually thereafter, renal function should be assessed. In patients in whom development of renal dysfunction is anticipated, particularly in elderly patients, renal function should be assessed more frequently and JANUMET or JANUMET XR discontinued if evidence of renal impairment is present.
Hypoglycemia With Concomitant Use With Insulin or Insulin Secretagogues
JANUMET or JANUMET XR may increase the risk of hypoglycemia when combined with insulin and/or an insulin secretagogue (eg, sulfonylurea). A lower dose of insulin or insulin secretagogue may be required to minimize the risk of hypoglycemia when used in combination with JANUMET or JANUMET XR.
The incidence (and rate) of hypoglycemia based on all reports of symptomatic hypoglycemia were: 16.4% (0.82 episodes/patient-year) for sitagliptin 100 mg in combination with metformin and glimepiride, 0.9% (0.02 episodes/patient-year) for placebo in combination with metformin and glimepiride, 8.2% (0.61 episodes/patient-year) for placebo in combination with metformin and insulin, and 15.3% (0.98 episodes/patient-year) for sitagliptin in combination with metformin and insulin.
There have been postmarketing reports of serious hypersensitivity reactions in patients treated with sitagliptin, one of the components of JANUMET and JANUMET XR, such as anaphylaxis, angioedema, and exfoliative skin conditions including Stevens-Johnson syndrome. Onset of these reactions occurred within the first 3 months after initiating sitagliptin, with some reports occurring after the first dose. If a hypersensitivity reaction is suspected, discontinue JANUMET or JANUMET XR, assess for other potential causes for the event, and institute alternative diabetes treatment.
Angioedema has also been reported with other DPP-4 inhibitors. Use caution in a patient with a history of angioedema to another DPP-4 inhibitor because it is unknown whether such patients will be predisposed to angioedema with JANUMET or JANUMET XR.
There have been postmarketing reports of severe and disabling arthralgia in patients taking DPP-4 inhibitors. The time to onset of symptoms following initiation of drug therapy varied from 1 day to years. Patients experienced relief of symptoms upon discontinuation of the medication. A subset of patients experienced a recurrence of symptoms when restarting the same drug or a different DPP-4 inhibitor. Consider DPP-4 inhibitors as a possible cause for severe joint pain and discontinue drug if appropriate.
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 JANUMET or JANUMET XR. If bullous pemphigoid is suspected, JANUMET or JANUMET XR should be discontinued and referral to a dermatologist should be considered for diagnosis and appropriate treatment.
In clinical studies, the most common adverse reactions reported, regardless of investigator assessment of causality, in ≥5% of patients treated with either sitagliptin in combination with metformin or placebo were as follows: diarrhea (7.5% vs 4.0%), upper respiratory tract infection (6.2% vs 5.1%), and headache (5.9% vs 2.8%). In patients treated with sitagliptin in combination with metformin and sulfonylurea or placebo in combination with metformin and sulfonylurea: hypoglycemia (16.4% vs 0.9%) and headache (6.9% vs 2.7%). In patients treated with sitagliptin in combination with metformin and insulin or placebo in combination with metformin and insulin: hypoglycemia (15.3% vs 8.2%). Other adverse events with an incidence of ≥5% included: nasopharyngitis for sitagliptin monotherapy; and hypoglycemia (13.7% vs 4.9%), diarrhea (12.5% vs 5.6%), and nausea (6.7% vs 4.2%) for extended-release metformin vs placebo when added to glyburide. Other adverse events with an incidence of ≥5% included diarrhea, nausea/vomiting, flatulence, abdominal discomfort, indigestion, asthenia, and headache for metformin immediate release.
Adverse reactions with sitagliptin in combination with metformin and rosiglitazone through Week 18 were: upper respiratory tract infection (sitagliptin, 5.5%; placebo, 5.2%) and nasopharyngitis (6.1%, 4.1%). Through Week 54 they were: upper respiratory tract infection (sitagliptin, 15.5%; placebo, 6.2%), nasopharyngitis (11.0%, 9.3%), peripheral edema (8.3%, 5.2%), and headache (5.5%, 4.1%).
Before prescribing JANUMET® (sitagliptin and metformin HCl) tablets or JANUMET® XR (sitagliptin and metformin HCl extended-release) tablets, please read the accompanying Prescribing Information, including the Boxed Warning about lactic acidosis. The Medication Guide for JANUMET or JANUMET XR also is available.
