GLYBURIDE AND METFORMIN HYDROCHLORIDE

Glyburide and Metformin Hydrochloride Tablets, USP contain 2 oral antihyperglycemic drugs used in the management of type 2 diabetes, glyburide, USP and metformin hydrochloride, USP. Glyburide, USP is an oral antihyperglycemic drug of the sulfonylurea class. The chemical name for glyburide is 1-[[ p -[2-(5-chloro- o -anisamido)ethyl]phenyl]sulfonyl]-3-cyclo-hexylurea. Glyburide, USP is a white or almost white, crystalline powder with a molecular formula of C 23 H 28 ClN 3 O 5 S and a molecular weight of 494. The glyburide used in glyburide and metformin hydrochloride tablets, USP has a particle size at least 20% are less than 2 micron, at least 80% are less than 10 micron and 100% are less than 40 micron. The structural formula is represented below. Metformin hydrochloride, USP is an oral antihyperglycemic drug used in the management of type 2 diabetes. Metformin hydrochloride ( N , N -dimethylimidodicarbonimidic diamide monohydrochloride) is not chemically or pharmacologically related to sulfonylureas, thiazolidinediones, or α-glucosidase inhibitors. It is a white crystals with a molecular formula of C 4 H 12 ClN 5 (monohydrochloride) and a molecular weight of 165.62. Metformin hydrochloride, USP is freely soluble in water, slightly soluble in ethanol (95%), practically insoluble in acetone and in methylene chloride. The structural formula is as shown: Each glyburide and metformin hydrochloride tablet, USP intended for oral administration contains 1.25 mg glyburide USP with 250 mg metformin hydrochloride USP, 2.5 mg glyburide USP with 500 mg metformin hydrochloride USP and 5 mg glyburide USP with 500 mg metformin hydrochloride USP. In addition, each tablet contains the following inactive ingredients: calcium carbonate, croscarmellose sodium, magnesium stearate, microcrystalline cellulose and povidone. Additionally, 1.25 mg/250 mg tablets contain opadry II white 33F28398 which contains hypromellose, lactose monohydrate, polyethylene glycol, talc and titanium dioxide. Additionally, 2.5 mg/500 mg tablets contain opadry II orange 31F530003 which contains FD&C blue #2 aluminum lake, FD&C yellow #5 aluminum lake, FD&C yellow #6 aluminum lake, hypromellose, lactose monohydrate, polyethylene glycol and titanium dioxide. Additionally, 5 mg/500 mg tablets contain opadry II green 31F510000 which contains iron oxide black, iron oxide red, iron oxide yellow, hypromellose, lactose monohydrate, polyethylene glycol and titanium dioxide. figure figure

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.

General Considerations Dosage of glyburide and metformin hydrochloride tablets 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 tablets 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), reduce GI side effects (largely due to metformin), and 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 tablets 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 tablets 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 Tablets 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 tablet 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 tablet 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 2 weeks up to the minimum effective dose necessary to achieve adequate control of blood glucose. In clinical trials of glyburide and metformin hydrochloride tablets as initial therapy, there was no experience with total daily doses >10 mg/2000 mg per day. Glyburide and metformin hydrochloride tablets 5 mg/500 mg should not be used as initial therapy due to an increased risk of hypoglycemia. Glyburide and Metformin Hydrochloride Tablets 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 tablet 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 tablets 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 tablets, 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 tablets should be titrated as described above to achieve adequate control of blood glucose. Addition of Thiazolidinediones to Glyburide and Metformin Hydrochloride Tablets Therapy For patients not adequately controlled on glyburide and metformin hydrochloride tablets, a thiazolidinedione can be added to glyburide and metformin hydrochloride tablets therapy. When a thiazolidinedione is added to glyburide and metformin hydrochloride tablets therapy, the current dose of glyburide and metformin hydrochloride tablets 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 tablets 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 tablets and a thiazolidinedione, consideration should be given to reducing the dose of the glyburide component of glyburide and metformin hydrochloride tablets. 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 tablets should be administered at least 4 hours prior to colesevelam. Specific Patient Populations Glyburide and metformin hydrochloride tablets are not recommended for use during pregnancy. The initial and maintenance dosing of glyburide and metformin hydrochloride tablets 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 tablets 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 . )

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. Concomitant administration of bosentan. Glyburide and metformin hydrochloride tablets 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 . )

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 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 Adverse Event Placebo N = 161 Glyburide N = 324 Metformin N = 312 Glyburide and Metformin Hydrochloride 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) 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) 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 1 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 1 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 Variable Placebo N = 161 Glyburide Tablets N = 160 Metformin Tablets N = 159 Glyburide and Metformin Hydrochloride 1 . 25 mg / 250 mg Tablets N = 158 Glyburide and Metformin Hydrochloride 2 . 5 mg / 500 mg Tablets 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) In postmarketing reports cholestatic jaundice and hepatitis may occur rarely which may progress to liver failure; glyburide and metformin hydrochloride should be discontinued if this occurs.

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 C max of 32% and 47%, respectively. The reductions in glyburide AUC and C max 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 C max by 22% and blood AUC by 15%, without any significant change in metformin renal clearance. When administered with metformin, the C max and AUC of furosemide were 31% and 12% smaller, respectively, than when administered alone, and the terminal half-life was decreased by 32%, without any significant change in furosemide renal clearance. No information is available about the interaction of metformin and furosemide when coadministered chronically. Nifedipine A single-dose, metformin-nifedipine drug interaction study in normal healthy volunteers demonstrated that coadministration of nifedipine increased plasma metformin C max and AUC by 20% and 9%, respectively, and increased the amount excreted in the urine. T max and half-life were unaffected. Nifedipine appears to enhance the absorption of metformin. Metformin had minimal effects on nifedipine. 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 coadministered in single-dose interaction studies.