Data from FDA - Curated by Toby Galbraith - Last updated 28 July 2017

Indication(s)

INDICATIONS AND USAGE Glyburide and metformin hydrochloride tablets, USP are indicated as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus.

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Advisory information

contraindications
CONTRAINDICATIONS Glyburide and metformin hydrochloride tablets are contraindicated in patients with: Severe renal impairment (eGFR below 30 mL/min/1.73m2) (see WARNINGS and PRECAUTIONS). Known hypersensitivity to metformin hydrochloride or glyburide. Acute or chronic metabolic acidosis, including diabetic ketoacidosis, with or without coma. Diabetic ketoacidosis should be treated with insulin. Concomitant administration of bosentan.
Special warnings and precautions
PRECAUTIONS Glyburide and Metformin Hydrochloride Lactic Acidosis There have been postmarketing cases of metformin-associated lactic acidosis, including fatal cases. These cases had a subtle onset and were accompanied by nonspecific symptoms such as malaise, myalgias, abdominal pain, respiratory distress, or increased somnolence; however, hypotension and resistant bradyarrhythmias have occurred with severe acidosis. Metformin-associated lactic acidosis was characterized by elevated blood lactate concentrations (>5 mmol/L), anion gap acidosis (without evidence of ketonuria or ketonemia), and an increased lactate:pyruvate ratio; metformin plasma levels were generally >5 mcg/mL. Metformin decreases liver uptake of lactate increasing lactate blood levels which may increase the risk of lactic acidosis, especially in patients at risk. If metformin-associated lactic acidosis is suspected, general supportive measures should be instituted promptly in a hospital setting, along with immediate discontinuation of glyburide and metformin hydrochloride. In glyburide and metformin hydrochloride treated patients with a diagnosis or strong suspicion of lactic acidosis, prompt hemodialysis is recommended to correct the acidosis and remove accumulated metformin (metformin hydrochloride is dialyzable with a clearance of up to 170 mL/min under good hemodynamic conditions). Hemodialysis has often resulted in reversal of symptoms and recovery. Educate patients and their families about the symptoms of lactic acidosis and if these symptoms occur instruct them to discontinue glyburide and metformin hydrochloride tablets and report these symptoms to their healthcare provider. For each of the known and possible risk factors for metformin-associated lactic acidosis, recommendations to reduce the risk of and manage metformin-associated lactic acidosis are provided below: Renal Impairment - The 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. Clinical recommendations based upon the patient’s renal function include (see DOSAGE AND ADMINISTRATION , CLINICAL PHARMACOLOGY ): Before initiating glyburide and metformin hydrochloride, obtain an estimated glomerular filtration rate (eGFR). Glyburide and metformin hydrochloride is contraindicated in patients with an eGFR less than 30 mL/min/1.73 m2 (see CONTRAINDICATIONS ). Initiation of glyburide and metformin hydrochloride is not recommended in patients with eGFR between 30 to 45 mL/min/1.73 m2. Obtain an eGFR at least annually in all patient taking glyburide and metformin hydrochloride. In patients at risk for the development of renal impairment (e.g., the elderly), renal function should be assessed more frequently. In patients taking glyburide and metformin hydrochloride whose eGFR falls below 45 mL/min/1.73 m2, assess the benefit and risk of continuing therapy. Drug Interactions -The concomitant use of glyburide and metformin hydrochloride 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. Age 65 or Greater - 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. Radiologic Studies with Contrast - 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 glyburide and metformin hydrochloride 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. Reevaluate eGFR 48 hours after the imaging procedure, and restart glyburide and metformin hydrochloride if renal function is stable. Surgery and Other Procedures - Withholding of food and fluids during surgical or other procedures may increase the risk for volume depletion, hypotension, and renal impairment. glyburide and metformin hydrochloride should be temporarily discontinued while patients have restricted food and fluid intake. Hypoxic States - Several of the postmarketing cases of metformin-associated lactic acidosis 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 cause prerenal azotemia. When such an event occurs, discontinue glyburide and metformin hydrochloride. Excessive 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 glyburide and metformin hydrochloride. Hepatic Impairment—Patients with hepatic impairment have developed cases of metformin-associated lactic acidosis. This may be due to impaired lactate clearance resulting in higher lactate blood levels. Therefore, avoid use of glyburide and metformin hydrochloride in patients with clinical or laboratory evidence of hepatic disease. Glyburide and Metformin Hydrochloride The glyburide component of glyburide and metformin HCl tablets is not bioequivalent to Micronase®. In addition, it has been reported that bioavailability studies have demonstrated that micronized glyburide tablets 3 mg provide serum glyburide concentration that are not bioequivalent to those from nonmicronized glyburide tablets 5 mg. Therefore, patients should be retitrated when transferred from micronized glyburide tablets or other oral hypoglycemic agents. Hypoglycemia Glyburide and metformin hydrochloride is capable of producing hypoglycemia or hypoglycemic symptoms, therefore, proper patient selection, dosing, and instructions are important to avoid potential hypoglycemic episodes. The risk of hypoglycemia is increased when caloric intake is deficient, when strenuous exercise is not compensated by caloric supplementation, or during concomitant use with other glucose-lowering agents or ethanol. Renal or hepatic insufficiency may cause elevated drug levels of both glyburide and metformin hydrochloride, and the hepatic insufficiency may also diminish gluconeogenic capacity, both of which increase the risk of hypoglycemic reactions. 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 beta-adrenergic blocking drugs. Glyburide Hemolytic Anemia Treatment of patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency with sulfonylurea agents can lead to hemolytic anemia. Because glyburide and metformin hydrochloride belongs to the class of sulfonylurea agents, caution should be used in patients with G6PD deficiency and a non-sulfonylurea alternative should be considered. In postmarketing reports, hemolytic anemia has also been reported in patients who did not have known G6PD deficiency. Metformin Hydrochloride Vitamin B12 Levels In controlled clinical trials with metformin of 29 weeks duration, a decrease to subnormal levels of previously normal serum vitamin B12, 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 metformin and any apparent abnormalities should be appropriately investigated and managed (see PRECAUTIONS: Laboratory Tests ). 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 2- to 3-year intervals may be useful. Macrovascular Outcomes There have been no clinical studies establishing conclusive evidence of macrovascular risk reduction with glyburide and metformin hydrochloride or any other antidiabetic drug. Addition of Thiazolidinediones to Glyburide and Metformin Hydrochloride Therapy Hypoglycemia Patients receiving glyburide and metformin hydrochloride in combination with a thiazolidinedione may be at risk for hypoglycemia. Weight Gain Weight gain was seen with the addition of rosiglitazone to glyburide and metformin hydrochloride, similar to that reported for thiazolidinedione therapy alone. Hepatic Effects When a thiazolidinedione is used in combination with glyburide and metformin hydrochloride, periodic monitoring of liver function tests should be performed in compliance with the labeled recommendations for the thiazolidinedione. Information for Patients Glyburide and Metformin Hydrochloride Patients should be informed of the potential risks and benefits of glyburide and metformin hydrochloride and alternative modes of therapy. They should also be informed about the importance of adherence to dietary instructions, a regular exercise program, and regular testing of blood glucose, glycosylated hemoglobin, renal function, and hematologic parameters. The risks of lactic acidosis associated with metformin therapy, its symptoms, and conditions that predispose to its development, as noted in the WARNINGS and PRECAUTIONS sections, should be explained to patients. Patients should be advised to discontinue glyburide and metformin hydrochloride immediately and promptly notify their health practitioner if unexplained hyperventilation, myalgia, malaise, unusual somnolence, or other nonspecific symptoms occur. Once a patient is stabilized on any dose level of glyburide and metformin hydrochloride, gastrointestinal symptoms, which are common during initiation of metformin therapy, are unlikely to be drug related. Later occurrence of gastrointestinal symptoms could be due to lactic acidosis or other serious disease. The risks of hypoglycemia, its symptoms and treatment, and conditions that predispose to its development should be explained to patients and responsible family members. Patients should be counseled against excessive alcohol intake, either acute or chronic, while receiving glyburide and metformin hydrochloride. (See Patient Information printed below.) Laboratory Tests Periodic fasting blood glucose (FBG) and HbA1c measurements should be performed to monitor therapeutic response. Initial and periodic monitoring of hematologic parameters (e.g., hemoglobin/hematocrit and red blood cell indices) and renal function (serum creatinine) should be performed, at least on an annual basis. While megaloblastic anemia has rarely been seen with metformin therapy, if this is suspected, vitamin B12 deficiency should be excluded. Instruct patients to inform their doctor that they are taking glyburide and metformin hydrochloride prior to any surgical or radiological procedure, as temporary discontinuation of glyburide and metformin hydrochloride may be required until renal function has been confirmed to be normal (see PRECAUTIONS ). Drug Interactions Glyburide and Metformin Hydrochloride Certain drugs tend to produce hyperglycemia and may lead to loss of blood glucose control. These drugs include 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 glyburide and metformin hydrochloride, the patient should be closely observed for loss of blood glucose control. When such drugs are withdrawn from a patient receiving glyburide and metformin hydrochloride, the patient should be observed closely for hypoglycemia. 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 sulfonylureas, which are extensively bound to serum proteins. Glyburide The hypoglycemic action of sulfonylureas may be potentiated by certain drugs, including nonsteroidal anti-inflammatory agents and other drugs that are highly protein bound, salicylates, sulfonamides, chloramphenicol, probenecid, coumarins, monoamine oxidase inhibitors, and beta-adrenergic blocking agents. When such drugs are administered to a patient receiving glyburide and metformin hydrochloride, the patient should be observed closely for hypoglycemia. When such drugs are withdrawn from a patient receiving glyburide and metformin hydrochloride, the patient should be observed closely for loss of blood glucose control. An increased risk of liver enzyme elevations was observed in patients receiving glyburide concomitantly with bosentan. Therefore concomitant administration of glyburide and metformin hydrochloride and bosentan is contraindicated. A possible interaction between glyburide and ciprofloxacin, a fluoroquinolone antibiotic, has been reported, resulting in a potentiation of the hypoglycemic action of glyburide. The mechanism for this interaction is not known. A potential interaction between oral miconazole and oral hypoglycemic agents leading to severe hypoglycemia has been reported. Whether this interaction also occurs with the intravenous, topical, or vaginal preparations of miconazole is not known. Colesevelam: Concomitant administration of colesevelam and glyburide resulted in reductions in glyburide AUC and Cmax of 32% and 47%, respectively. The reductions in glyburide AUC and Cmax were 20% and 15%, respectively, when administered 1 hour before, and not significantly changed (-7% and 4%, respectively) when administered 4 hours before colesevelam. Metformin Hydrochloride 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 Cmax by 22% and blood AUC by 15%, without any significant change in metformin renal clearance. When administered with metformin, the Cmax 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 Cmax and AUC by 20% and 9%, respectively, and increased the amount excreted in the urine. Tmax 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 transport-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 accumulation of metformin and the risk for lactic acidosis. Consider the benefits and risks of concomitant use. Such interaction between metformin and oral cimetidine has been observed in normal healthy volunteers in both single- and multiple-dose, metformin-cimetidine drug interaction studies, with a 60% increase in peak metformin plasma and whole blood concentrations and a 40% increase in plasma and whole blood metformin AUC. There was no change in elimination half-life in the single-dose study. Metformin had no effect on cimetidine pharmacokinetics. 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. Carbonic Anhydrase Inhibitors Topiramate or other carbonic anhydrase inhibitors (e.g., zonisamide, acetazolamide or dichlorphenamide) frequently causes a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of these drugs with glyburide and metformin hydrochloride may increase the risk for lactic acidosis. Consider more frequent monitoring of these patients. Alcohol Alcohol is known to potentiate the effects of metformin on lactate metabolism. Warn patients against excessive alcohol intake while receiving glyburide and metformin hydrochloride. Carcinogenesis, Mutagenesis, Impairment of Fertility No animal studies have been conducted with the combined products in glyburide and metformin hydrochloride. The following data are based on findings in studies performed with the individual products. Glyburide Studies in rats with glyburide alone at doses up to 300 mg/kg/day (approximately 145 times the maximum recommended human daily [MRHD] dose of 20 mg for the glyburide component of glyburide and metformin hydrochloride based on body surface area comparisons) for 18 months revealed no carcinogenic effects. In a two-year oncogenicity study of glyburide in mice, there was no evidence of treatment-related tumors. There was no evidence of mutagenic potential of glyburide alone in the following in vitro tests: Salmonella microsome test (Ames test) and in the DNA damage/alkaline elution assay. Metformin Hydrochloride ​Long-term carcinogenicity studies were performed with metformin alone in rats (dosing duration of 104 weeks) and mice (dosing duration of 91 weeks) at doses up to and including 900 mg/kg/day and 1500 mg/kg/day, respectively. These doses are both approximately four times the MRHD dose of 2000 mg of the metformin component of glyburide and metformin hydrochloride based on body surface area comparisons. No evidence of carcinogenicity with metformin alone was found in either male or female mice. Similarly, there was no tumorigenic potential observed with metformin alone in male rats. There was, however, an increased incidence of benign stromal uterine polyps in female rats treated with 900 mg/kg/day of metformin alone. There was no evidence of a mutagenic potential of metformin alone in the following in vitro tests: Ames test (S. typhimurium), gene mutation test (mouse lymphoma cells), or chromosomal aberrations test (human lymphocytes). Results in the in vivo mouse micronucleus test were also negative. Fertility of male or female rats was unaffected by metformin alone when administered at doses as high as 600 mg/kg/day, which is approximately three times the MRHD dose of the metformin component of glyburide and metformin hydrochloride based on body surface area comparisons. Pregnancy Teratogenic Effects: Pregnancy Category B Recent information strongly suggests that abnormal blood glucose levels during pregnancy are associated with a higher incidence of congenital abnormalities. Most experts recommend that insulin be used during pregnancy to maintain blood glucose as close to normal as possible. Because animal reproduction studies are not always predictive of human response, glyburide and metformin hydrochloride should not be used during pregnancy unless clearly needed. (See below.) There are no adequate and well-controlled studies in pregnant women with glyburide and metformin hydrochloride or its individual components. No animal studies have been conducted with the combined products in glyburide and metformin hydrochloride. The following data are based on findings in studies performed with the individual products. Glyburide Reproduction studies were performed in rats and rabbits at doses up to 500 times the MRHD dose of 20 mg of the glyburide component of glyburide and metformin hydrochloride based on body surface area comparisons and revealed no evidence of impaired fertility or harm to the fetus due to glyburide. Metformin Hydrochloride Metformin alone was not teratogenic in rats or rabbits at doses up to 600 mg/kg/day. This represents an exposure of about two and six times the MRHD dose of 2000 mg of the metformin component of glyburide and metformin hydrochloride based on body surface area comparisons for rats and rabbits, respectively. Determination of fetal concentrations demonstrated a partial placental barrier to metformin. Nonteratogenic Effects Prolonged severe hypoglycemia (4 to 10 days) has been reported in neonates born to mothers who were receiving a sulfonylurea drug at the time of delivery. This has been reported more frequently with the use of agents with prolonged half-lives. It is not recommended that glyburide and metformin hydrochloride be used during pregnancy. However, if it is used, glyburide and metformin hydrochloride should be discontinued at least two weeks before the expected delivery date (see Pregnancy: Teratogenic Effects: Pregnancy Category B ). Nursing Mothers Although it is not known whether glyburide is excreted in human milk, some sulfonylurea drugs are known to be excreted in human milk. Studies in lactating rats show that metformin is excreted into milk and reaches levels comparable to those in plasma. Similar studies have not been conducted in nursing mothers. Because the potential for hypoglycemia in nursing infants may exist, a decision should be made whether to discontinue nursing or to discontinue glyburide and metformin hydrochloride, taking into account the importance of the drug to the mother. If glyburide and metformin hydrochloride is discontinued, and if diet alone is inadequate for controlling blood glucose, insulin therapy should be considered. Pediatric Use The safety and efficacy of glyburide and metformin hydrochloride was evaluated in an active-controlled, double-blind, 26-week randomized trial involving a total of 167 pediatric patients (ranging from 9 to 16 years of age) with type 2 diabetes. Glyburide and metformin hydrochloride was not shown statistically to be superior to either metformin or glyburide with respect to reducing HbA1c from baseline (see Table 5). No unexpected safety findings were associated with glyburide and metformin hydrochloride in this trial. Table 5: HbA1c (Percent) Change From Baseline at 26 Weeks: Pediatric Study Glyburide and Metformin Glyburide Metformin Hydrochloride 2.5 mg 500 mg 1.25 mg/250 mg Tablets Tablets Tablets Mean Final Dose 6.5 mg 1500 mg 3.1 mg/623 mg Hemoglobin A1c N=49 N=54 N=57 Baseline Mean (%) 7.70 7.99 7.85 Mean Change from Baseline -0.96 -0.48 -0.80 Difference from Metformin -0.32 Difference from Glyburide +0.16 Geriatric Use Of the 642 patients who received glyburide and metformin hydrochloride in double-blind clinical studies, 23.8% were 65 and older while 2.8% were 75 and older. Of the 1302 patients who received glyburide and metformin hydrochloride in open-label clinical studies, 20.7% were 65 and older while 2.5% were 75 and older. No overall differences in effectiveness or safety were observed between these patients and younger patients, and other reported clinical experience has not identified differences in response between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy and the higher risk of lactic acidosis. Assess renal function more frequently in elderly patients (see also WARNINGS, PRECAUTIONS, and DOSAGE AND ADMINISTRATION ).
Adverse reactions
ADVERSE REACTIONS Glyburide and Metformin Hydrochloride In double-blind clinical trials involving glyburide and metformin hydrochloride as initial therapy or as second-line therapy, a total of 642 patients received the combination product glyburide and metformin hydrochloride, 312 received metformin therapy, 324 received glyburide therapy, and 161 received placebo. The percent of patients reporting events and types of adverse events reported in clinical trials of glyburide and metformin hydrochloride (all strengths) as initial therapy and second-line therapy are listed in Table 6. Table 6: Most Common Clinical Adverse Events (>5%) in Double-Blind Clinical Studies of Glyburide and Metformin Hydrochloride Used as Initial or Second-Line Therapy Number (%) of Patients Glyburide and Metformin Adverse Event Placebo Glyburide Metformin Hydrochloride N=161 N=324 N=312 N=642 Upper respiratory infection 22 (13.7) 57 (17.6) 51 (16.3) 111 (17.3) Diarrhea 9 (5.6) 20 (6.2) 64 (20.5) 109 (17.0) Headache 17 (10.6) 37 (11.4) 29 (9.3) 57 (8.9) Nausea/vomiting 10 (6.2) 17 (5.2) 38 (12.2) 49 (7.6) Abdominal pain 6 (3.7) 10 (3.1) 25 (8.0) 44 (6.9) Dizziness 7 (4.3) 18 (5.6) 12 (3.8) 35 (5.5) In a controlled clinical trial of rosiglitazone versus placebo in patients treated with glyburide and metformin hydrochloride (n=365), 181 patients received glyburide and metformin hydrochloride with rosiglitazone and 184 received glyburide and metformin hydrochloride with placebo. Edema was reported in 7.7% (14/181) of patients treated with rosiglitazone compared to 2.2% (4/184) of patients treated with placebo. A mean weight gain of 3 kg was observed in rosiglitazone-treated patients. Disulfiram-like reactions have very rarely been reported in patients treated with glyburide tablets. Hypoglycemia In controlled clinical trials of glyburide and metformin hydrochloride there were no hypoglycemic episodes requiring medical intervention and/or pharmacologic therapy; all events were managed by the patients. The incidence of reported symptoms of hypoglycemia (such as dizziness, shakiness, sweating, and hunger), in the initial therapy trial of glyburide and metformin hydrochloride are summarized in Table 7. The frequency of hypoglycemic symptoms in patients treated with glyburide and metformin hydrochloride 1.25 mg/250 mg was highest in patients with a baseline HbA1c <7%, lower in those with a baseline HbA1c of between 7% and 8%, and was comparable to placebo and metformin in those with a baseline HbA1c >8%. For patients with a baseline HbA1c between 8% and 11% treated with glyburide and metformin hydrochloride 2.5 mg/500 mg as initial therapy, the frequency of hypoglycemic symptoms was 30% to 35%. As second-line therapy in patients inadequately controlled on sulfonylurea alone, approximately 6.8% of all patients treated with glyburide and metformin hydrochloride experienced hypoglycemic symptoms. When rosiglitazone was added to glyburide and metformin hydrochloride therapy, 22% of patients reported one or more fingerstick glucose measurements ≤50 mg/dL compared to 3.3% of placebo-treated patients. All hypoglycemic events were managed by the patients and only one patient discontinued for hypoglycemia (see PRECAUTIONS: General: Addition of Thiazolidinediones to Glyburide and Metformin Hydrochloride Therapy). Gastrointestinal Reactions The incidence of gastrointestinal (GI) side effects (diarrhea, nausea/vomiting, and abdominal pain) in the initial therapy trial are summarized in Table 7. Across all glyburide and metformin hydrochloride trials, GI symptoms were the most common adverse events with glyburide and metformin hydrochloride and were more frequent at higher dose levels. In controlled trials, <2% of patients discontinued glyburide and metformin hydrochloride therapy due to GI adverse events. Table 7: Treatment Emergent Symptoms of Hypoglycemia or Gastrointestinal Adverse Events in a Placebo-and Active-Controlled Trial of Glyburide and Metformin Hydrochloride as Initial Therapy Glyburide and Glyburide and Metformin Metformin Hydrochloride Hydrochloride Placebo Glyburide Metformin 1.25 mg/250 mg 2.5 mg/500 mg Variable Tablets Tablets Tablets Tablets N=161 N=160 N=159 N=158 N=162 Mean Final Dose 0 mg 5.3 mg 1317 mg 2.78 mg/557 mg 4.1 mg/824 mg Number (%) of patients with symptoms of hypoglycemia 5 (3.1) 34 (21.3) 5 (3.1) 18 (11.4) 61 (37.7) Number (%) of patients with gastrointestinal adverse events 39 (24.2) 38 (23.8) 69 (43.3) 50 (31.6) 62 (38.3) Metformin Hydrochloride Cholestatic, hepatocellular, and mixed hepatocellular liver injury have been reported with postmarketing use of metformin. Glyburide Gastrointestinal Reactions Cholestatic jaundice and hepatitis may occur rarely which may progress to liver failure; the drug should be discontinued if this occurs. Liver function abnormalities, including isolated transaminase elevations, have been reported. Dermatologic Reactions Allergic skin reactions, eg, pruritus, erythema, urticaria, and morbilliform or maculopapular eruptions, occur in 1.5% of glyburide-treated patients. These may be transient and may disappear despite continued use; if skin reactions persist, the drug should be discontinued. Postmarketing Adverse Reactions The following adverse reactions have been identified during post-approval use. 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. Allergic: Angioedema, arthralgia, myalgia, and vasculitis have been reported. Dermatologic: Porphyria cutanea tarda and photosensitivity reactions have been reported with sulfonylureas. Hematologic: Leukopenia, agranulocytosis, thrombocytopenia, which occasionally may present as purpura, hemolytic anemia, aplastic anemia, and pancytopenia, have been reported with sulfonylureas. Metabolic: Hepatic porphyria reactions have been reported with sulfonylureas; however, these have not been reported with glyburide. Disulfiram-like reactions have been reported very rarely with glyburide. Cases of hyponatremia have been reported with glyburide and all other sulfonylureas, most often in patients who are on other medications or have medical conditions known to cause hyponatremia or increase release of antidiuretic hormone. Other Reactions: Changes in accommodation and/or blurred vision have been reported with glyburide and other sulfonylureas. These are thought to be related to fluctuation in glucose levels. To report SUSPECTED ADVERSE EVENTS, contact Actavis at 1-800-432-8534 or FDA at 1-800-FDA-1088 or http://www.fda.gov/ for voluntary reporting of adverse reactions.

Usage information

Dosing and administration
DOSAGE AND ADMINISTRATION General Considerations Dosage of glyburide and metformin hydrochloride must be individualized on the basis of both effectiveness and tolerance while not exceeding the maximum recommended daily dose of 20 mg glyburide/2000 mg metformin. Glyburide and metformin hydrochloride should be given with meals and should be initiated at a low dose, with gradual dose escalation as described below, in order to avoid hypoglycemia (largely due to glyburide), to reduce GI side effects (largely due to metformin), and to permit determination of the minimum effective dose for adequate control of blood glucose for the individual patient. With initial treatment and during dose titration, appropriate blood glucose monitoring should be used to determine the therapeutic response to glyburide and metformin hydrochloride and to identify the minimum effective dose for the patient. Thereafter, HbA1c should be measured at intervals of approximately 3 months to assess the effectiveness of therapy. The therapeutic goal in all patients with type 2 diabetes is to decrease FPG, PPG, and HbA1c to normal or as near normal as possible. Ideally, the response to therapy should be evaluated using HbA1c (glycosylated hemoglobin), which is a better indicator of long-term glycemic control than FPG alone. No studies have been performed specifically examining the safety and efficacy of switching to glyburide and metformin hydrochloride therapy in patients taking concomitant glyburide (or other sulfonylurea) plus metformin. Changes in glycemic control may occur in such patients, with either hyperglycemia or hypoglycemia possible. Any change in therapy of type 2 diabetes should be undertaken with care and appropriate monitoring. In Patients with Inadequate Glycemic Control on Diet and Exercise Recommended starting dose: 1.25 mg/250 mg once or twice daily with meals. For patients with type 2 diabetes whose hyperglycemia cannot be satisfactorily managed with diet and exercise alone, the recommended starting dose of glyburide and metformin hydrochloride is 1.25 mg/250 mg once a day with a meal. As initial therapy in patients with baseline HbA1c >9% or an FPG >200 mg/dL, a starting dose of glyburide and metformin hydrochloride 1.25 mg/250 mg twice daily with the morning and evening meals may be used. Dosage increases should be made in increments of 1.25 mg/250 mg per day every two weeks up to the minimum effective dose necessary to achieve adequate control of blood glucose. In clinical trials of glyburide and metformin hydrochloride as initial therapy, there was no experience with total daily doses >10 mg/2000 mg per day. Glyburide and metformin hydrochloride 5 mg/500 mg should not be used as initial therapy due to an increased risk of hypoglycemia. Glyburide and Metformin Hydrochloride Use in Patients with Inadequate Glycemic Control on a Sulfonylurea and/or Metformin Recommended starting dose: 2.5 mg/500 mg or 5 mg/500 mg twice daily with meals. For patients not adequately controlled on either glyburide (or another sulfonylurea) or metformin alone, the recommended starting dose of glyburide and metformin hydrochloride is 2.5 mg/500 mg or 5 mg/500 mg twice daily with the morning and evening meals. In order to avoid hypoglycemia, the starting dose of glyburide and metformin hydrochloride should not exceed the daily doses of glyburide or metformin already being taken. The daily dose should be titrated in increments of no more than 5 mg/500 mg up to the minimum effective dose to achieve adequate control of blood glucose or to a maximum dose of 20 mg/2000 mg per day. For patients previously treated with combination therapy of glyburide (or another sulfonylurea) plus metformin, if switched to glyburide and metformin hydrochloride, the starting dose should not exceed the daily dose of glyburide (or equivalent dose of another sulfonylurea) and metformin already being taken. Patients should be monitored closely for signs and symptoms of hypoglycemia following such a switch and the dose of glyburide and metformin hydrochloride should be titrated as described above to achieve adequate control of blood glucose. Addition of Thiazolidinediones to Glyburide and Metformin Hydrochloride Therapy For patients not adequately controlled on glyburide and metformin hydrochloride, a thiazolidinedione can be added to glyburide and metformin hydrochloride therapy. When a thiazolidinedione is added to glyburide and metformin hydrochloride therapy, the current dose of glyburide and metformin hydrochloride can be continued and the thiazolidinedione initiated at its recommended starting dose. For patients needing additional glycemic control, the dose of the thiazolidinedione can be increased based on its recommended titration schedule. The increased glycemic control attainable with glyburide and metformin hydrochloride plus a thiazolidinedione may increase the potential for hypoglycemia at any time of day. In patients who develop hypoglycemia when receiving glyburide and metformin hydrochloride and a thiazolidinedione, consideration should be given to reducing the dose of the glyburide component of glyburide and metformin hydrochloride. As clinically warranted, adjustment of the dosages of the other components of the antidiabetic regimen should also be considered. Patients Receiving Colesevelam When colesevelam is coadministered with glyburide, maximum plasma concentration and total exposure to glyburide is reduced. Therefore, glyburide and metformin hydrochloride should be administered at least 4 hours prior to colesevelam. Recommendations for Use in Renal Impairment Assess renal function prior to initiation of glyburide and metformin hydrochloride and periodically thereafter. Glyburide and metformin hydrochloride is contraindicated in patients with an estimated glomerular filtration rate (eGFR) below 30 mL/min/1.73 m2. Initiation of glyburide and metformin hydrochloride in patients with an eGFR between 30 to 45 mL/min/1.73 m2 is not recommended. In patients taking glyburide and metformin hydrochloride whose eGFR later falls below 45 mL/min/1.73 m2, assess the benefit risk of continuing therapy. Discontinue glyburide and metformin hydrochloride if the patient’s eGFR later falls below 30 mL/min/1.73 m2 (see WARNINGS and PRECAUTIONS .). Discontinuation for Iodinated Contrast Imaging Procedures Discontinue glyburide and metformin hydrochloride 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 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 glyburide and metformin hydrochloride if renal function is stable. Specific Patient Populations Glyburide and metformin hydrochloride is not recommended for use during pregnancy. The initial and maintenance dosing of glyburide and metformin hydrochloride should be conservative in patients with advanced age, due to the potential for decreased renal function in this population. Any dosage adjustment requires a careful assessment of renal function.
Pregnancy and lactation
Nursing Mothers Although it is not known whether glyburide is excreted in human milk, some sulfonylurea drugs are known to be excreted in human milk. Studies in lactating rats show that metformin is excreted into milk and reaches levels comparable to those in plasma. Similar studies have not been conducted in nursing mothers. Because the potential for hypoglycemia in nursing infants may exist, a decision should be made whether to discontinue nursing or to discontinue glyburide and metformin hydrochloride, taking into account the importance of the drug to the mother. If glyburide and metformin hydrochloride is discontinued, and if diet alone is inadequate for controlling blood glucose, insulin therapy should be considered.

Interactions

Drug Interactions Glyburide and Metformin Hydrochloride Certain drugs tend to produce hyperglycemia and may lead to loss of blood glucose control. These drugs include 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 glyburide and metformin hydrochloride, the patient should be closely observed for loss of blood glucose control. When such drugs are withdrawn from a patient receiving glyburide and metformin hydrochloride, the patient should be observed closely for hypoglycemia. 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 sulfonylureas, which are extensively bound to serum proteins. Glyburide The hypoglycemic action of sulfonylureas may be potentiated by certain drugs, including nonsteroidal anti-inflammatory agents and other drugs that are highly protein bound, salicylates, sulfonamides, chloramphenicol, probenecid, coumarins, monoamine oxidase inhibitors, and beta-adrenergic blocking agents. When such drugs are administered to a patient receiving glyburide and metformin hydrochloride, the patient should be observed closely for hypoglycemia. When such drugs are withdrawn from a patient receiving glyburide and metformin hydrochloride, the patient should be observed closely for loss of blood glucose control. An increased risk of liver enzyme elevations was observed in patients receiving glyburide concomitantly with bosentan. Therefore concomitant administration of glyburide and metformin hydrochloride and bosentan is contraindicated. A possible interaction between glyburide and ciprofloxacin, a fluoroquinolone antibiotic, has been reported, resulting in a potentiation of the hypoglycemic action of glyburide. The mechanism for this interaction is not known. A potential interaction between oral miconazole and oral hypoglycemic agents leading to severe hypoglycemia has been reported. Whether this interaction also occurs with the intravenous, topical, or vaginal preparations of miconazole is not known. Colesevelam: Concomitant administration of colesevelam and glyburide resulted in reductions in glyburide AUC and Cmax of 32% and 47%, respectively. The reductions in glyburide AUC and Cmax were 20% and 15%, respectively, when administered 1 hour before, and not significantly changed (-7% and 4%, respectively) when administered 4 hours before colesevelam. Metformin Hydrochloride 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 Cmax by 22% and blood AUC by 15%, without any significant change in metformin renal clearance. When administered with metformin, the Cmax 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 Cmax and AUC by 20% and 9%, respectively, and increased the amount excreted in the urine. Tmax 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 transport-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 accumulation of metformin and the risk for lactic acidosis. Consider the benefits and risks of concomitant use. Such interaction between metformin and oral cimetidine has been observed in normal healthy volunteers in both single- and multiple-dose, metformin-cimetidine drug interaction studies, with a 60% increase in peak metformin plasma and whole blood concentrations and a 40% increase in plasma and whole blood metformin AUC. There was no change in elimination half-life in the single-dose study. Metformin had no effect on cimetidine pharmacokinetics. 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. Carbonic Anhydrase Inhibitors Topiramate or other carbonic anhydrase inhibitors (e.g., zonisamide, acetazolamide or dichlorphenamide) frequently causes a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of these drugs with glyburide and metformin hydrochloride may increase the risk for lactic acidosis. Consider more frequent monitoring of these patients. Alcohol Alcohol is known to potentiate the effects of metformin on lactate metabolism. Warn patients against excessive alcohol intake while receiving glyburide and metformin hydrochloride.

More information

Category Value
Authorisation number ANDA076716
Agency product number SX6K58TVWC
Orphan designation No
Product NDC 0228-2752,0228-2753,0228-2751
Date Last Revised 26-06-2017
Type HUMAN PRESCRIPTION DRUG
RXCUI 861753
Marketing authorisation holder Actavis Pharma, Inc.
Warnings 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 (see PRECAUTIONS). Risk factors for metformin-associated lactic acidosis include renal impairment, concomitant use of certain drugs (e.g., carbonic anhydrase inhibitors such as topiramate), age 65 years old or greater, having a radiological study with contrast, surgery and other procedures, hypoxic states (e.g. acute congestive heart failure), excessive alcohol intake, and hepatic impairment. Steps to reduce the risk of and manage metformin-associated lactic acidosis in these high risk groups are provided (see DOSAGE AND ADMINISTRATION, CONTRAINDICATIONS, and PRECAUTIONS ). If metformin-associated lactic acidosis is suspected, immediately discontinue glyburide and metformin hydrochloride tablets and institute general supportive measures in a hospital setting. Prompt hemodialysis is recommended (see PRECAUTIONS ).