Data from FDA - Curated by Marshall Pearce - Last updated 24 October 2017

Indication(s)

INDICATIONS AND USAGE Glyburide and Metformin Hydrochloride Tablets 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: Renal disease or renal dysfunction (eg., as suggested by serum creatinine levels ≥ 1.5 mg/dL [males], ≥ 1.4 mg/dL [females], or abnormal creatinine clearance) which may also result from conditions such as cardiovascular collapse (shock), acute myocardial infarction, and septicemia (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. Glyburide and Metformin Hydrochloride should be temporarily discontinued in patients undergoing radiologic studies involving intravascular administration of iodinated contrast materials, because use of such products may result in acute alteration of renal function. (See also PRECAUTIONS.) WARNINGS Metformin Hydrochloride
Special warnings and precautions
PRECAUTIONS General Macrovascular Outcomes There have been no clinical studies establishing conclusive evidence of macrovascular risk reduction with Glyburide and Metformin Hydrochloride or any other anti-diabetic drug. 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 Monitoring of renal function Metformin is known to be substantially excreted by the kidney, and the risk of metformin accumulation and lactic acidosis increases with the degree of impairment of renal function. Thus, patients with serum creatinine levels above the upper limit of normal for their age should not receive Glyburide and Metformin Hydrochloride. In patients with advanced age, Glyburide and Metformin Hydrochloride should be carefully titrated to establish the minimum dose for adequate glycemic effect, because aging is associated with reduced renal function. In elderly patients, particularly those ≥ 80 years of age, renal function should be monitored regularly and, generally, Glyburide and Metformin Hydrochloride should not be titrated to the maximum dose (see WARNINGS and DOSAGE AND ADMINISTRATION). Before initiation of Glyburide and Metformin Hydrochloride therapy and at least annually thereafter, renal function should be assessed and verified as normal. In patients in whom development of renal dysfunction is anticipated, renal function should be assessed more frequently and Glyburide and Metformin Hydrochloride discontinued if evidence of renal impairment is present. 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 PRECAUTIONS: Drug 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 in whom any such study is planned, Glyburide and Metformin Hydrochloride 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 reevaluated and found to be normal. 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 Glyburide and Metformin Hydrochloride therapy, the drug should be promptly discontinued. Surgical procedures Glyburide and Metformin Hydrochloride therapy 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 normal. 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. Due to its effect on the gluconeogenic capacity of the liver, alcohol may also increase the risk of hypoglycemia. Impaired hepatic function Since impaired hepatic function has been associated with some cases of lactic acidosis, Glyburide and Metformin Hydrochloride should generally be avoided in patients with clinical or laboratory evidence of hepatic disease. Vitamin B 12 levels In controlled clinical trials with metformin of 29 weeks duration, a decrease to subnormal levels of previously normal serum Vitamin B 12, without clinical manifestations, was observed in approximately 7% of patients. Such decrease, possibly due to interference with B 12 absorption from the B 12-intrinsic factor complex, is, however, very rarely associated with anemia and appears to be rapidly reversible with discontinuation of metformin or Vitamin B 12 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 B 12 or calcium intake or absorption) appear to be predisposed to developing subnormal Vitamin B 12 levels. In these patients, routine serum Vitamin B 12 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 metformin 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, Glyburide and Metformin Hydrochloride must be stopped immediately and other appropriate corrective measures initiated (see also WARNINGS). 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 of alternative modes of therapy. They should also be informed about the importance of adherence to dietary instructions, of a regular exercise program, and of 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 to 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 HbA 1c measurements should be performed to monitor therapeutic response. Initial and periodic monitoring of hematologic parameters (eg, 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 B 12 deficiency should be excluded. Drug Interactions Glyburide and Metformin Hydrochloride Certain drugs tend to produce hyperglycemia and may lead to loss of blood glucose 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 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. 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. Metformin Hydrochloride Furosemide A single-dose, metformin-furosemide drug interaction study in healthy subjects demonstrated that pharmacokinetic parameters of both compounds were affected by co-administration. 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 co-administered chronically. Nifedipine A single-dose, metformin-nifedipine drug interaction study in normal healthy volunteers demonstrated that co-administration 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. Cationic drugs Cationic drugs (eg, amiloride, digoxin, morphine, procainamide, quinidine, quinine, ranitidine, triamterene, trimethoprim, or vancomycin) that are eliminated by renal tubular secretion theoretically have the potential for interaction with metformin by competing for common renal tubular transport systems. 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. Although such interactions remain theoretical (except for cimetidine), careful patient monitoring and dose adjustment of Glyburide and Metformin Hydrochloride and/or the interfering drug is recommended in patients who are taking cationic medications that are excreted via the proximal renal tubular secretory system. Other In healthy volunteers, the pharmacokinetics of metformin and propranolol and metformin and ibuprofen were not affected when co-administered in single-dose interaction studies. 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 maximum recommended human daily 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 HbA 1c from baseline (see Table 5). No unexpected safety findings were associated with Glyburide and Metformin Hydrochloride in this trial. Table 5: HbA 1c (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 A 1c 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. Metformin hydrochloride is known to be substantially excreted by the kidney and because the risk of serious adverse reactions to the drug is greater in patients with impaired renal function, Glyburide and Metformin Hydrochloride should only be used in patients with normal renal function (see CONTRAINDICATIONS, WARNINGS, and CLINICAL PHARMACOLOGY: Pharmacokinetics). Because aging is associated with reduced renal function, Glyburide and Metformin Hydrochloride 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. Generally, elderly patients should not be titrated to the maximum dose of Glyburide and Metformin Hydrochloride (see also WARNINGS 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 HbA 1c <7%, lower in those with a baseline HbA 1c of between 7% and 8%, and was comparable to placebo and metformin in those with a baseline HbA 1c >8%. For patients with a baseline HbA 1c 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)

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, HbA 1c 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 HbA 1c to normal or as near normal as possible. Ideally, the response to therapy should be evaluated using HbA 1c (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. Glyburide and Metformin Hydrochloride 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 HbA 1c >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 greater than 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. 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. Generally, elderly, debilitated, and malnourished patients should not be titrated to the maximum dose of Glyburide and Metformin Hydrochloride to avoid the risk of hypoglycemia. Monitoring of renal function is necessary to aid in prevention of metformin-associated lactic acidosis, particularly in the elderly. (See WARNINGS.)
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 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 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. 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. Metformin Hydrochloride Furosemide A single-dose, metformin-furosemide drug interaction study in healthy subjects demonstrated that pharmacokinetic parameters of both compounds were affected by co-administration. 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 co-administered chronically. Nifedipine A single-dose, metformin-nifedipine drug interaction study in normal healthy volunteers demonstrated that co-administration 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. Cationic drugs Cationic drugs (eg, amiloride, digoxin, morphine, procainamide, quinidine, quinine, ranitidine, triamterene, trimethoprim, or vancomycin) that are eliminated by renal tubular secretion theoretically have the potential for interaction with metformin by competing for common renal tubular transport systems. 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. Although such interactions remain theoretical (except for cimetidine), careful patient monitoring and dose adjustment of Glyburide and Metformin Hydrochloride and/or the interfering drug is recommended in patients who are taking cationic medications that are excreted via the proximal renal tubular secretory system. Other In healthy volunteers, the pharmacokinetics of metformin and propranolol and metformin and ibuprofen were not affected when co-administered in single-dose interaction studies.

More information

Category Value
Authorisation number ANDA076716
Agency product number SX6K58TVWC
Orphan designation No
Product NDC 43063-397
Date Last Revised 09-10-2017
Type HUMAN PRESCRIPTION DRUG
RXCUI 861753
Marketing authorisation holder PD-Rx Pharmaceuticals, Inc.
Warnings Lactic Acidosis Lactic acidosis is a rare, but serious, metabolic complication that can occur due to metformin accumulation during treatment with Glyburide and Metformin Hydrochloride tablets; 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. 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. A combination of Glyburide and Metformin Hydrochloride treatment should not be initiated in patients > 80 years of age unless measurement of creatinine clearance demonstrates that renal function is not reduced, as these patients are more susceptible to developing lactic acidosis. In addition, Glyburide and Metformin Hydrochloride 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, Glyburide and Metformin Hydrochloride 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 Glyburide and Metformin Hydrochloride, since alcohol potentiates the effects of metformin hydrochloride on lactate metabolism. In addition, Glyburide and Metformin Hydrochloride should be temporarily discontinued prior to any intravascular radiocontrast study and for any surgical procedure (see also PRECAUTIONS ). 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 (see also PRECAUTIONS ). Glyburide and Metformin Hydrochloride 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 Glyburide and Metformin Hydrochloride, gastrointestinal symptoms, which are common during initiation of therapy with metformin, 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 Glyburide and Metformin Hydrochloride 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. (See also PRECAUTIONS. ) 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 Glyburide and Metformin Hydrochloride, 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 also CONTRAINDICATIONS and PRECAUTIONS.)