Label: GLIPIZIDE AND METFORMIN HYDROCHLORIDE tablet, film coated

Absorption and Bioavailability

Distribution

Metabolism and Elimination

Patients With Type 2 Diabetes

In the presence of normal renal function, there are no differences between single- or multiple-dose pharmacokinetics of metformin between patients with type 2 diabetes and normal subjects (see Table 1), nor is there any accumulation of metformin in either group at usual clinical doses.

Renal Impairment

The metabolism and excretion of glipizide may be slowed in patients with impaired renal function (see CONTRAINDICATIONS, WARNINGS, PRECAUTIONS, and DOSAGE AND ADMINISTRATION).

In patients with decreased renal function, the plasma and blood half-life of metformin is prolonged and the renal clearance is decreased (see Table 1; also, see WARNINGS).

Hepatic Impairment

The metabolism and excretion of glipizide may be slowed in patients with impaired hepatic function (see PRECAUTIONS).

No pharmacokinetic studies have been conducted in patients with hepatic insufficiency for metformin.

Geriatrics

There is no information on the pharmacokinetics of glipizide in elderly patients.

Limited data from controlled pharmacokinetic studies of metformin in healthy elderly subjects suggest that total plasma clearance is decreased, the half-life is prolonged, and C max is increased, when compared to healthy young subjects. From these data, it appears that the change in metformin pharmacokinetics with aging is primarily accounted for by a change in renal function (see Table 1).

Pediatrics

No data from pharmacokinetic studies in pediatric subjects are available for glipizide.

After administration of a single oral metformin 500 mg tablet with food, geometric mean metformin C max and AUC differed < 5% between pediatric type 2 diabetic patients (12 to 16 years of age) and gender- and weight-matched healthy adults (20 to 45 years of age), all with normal renal function.

Gender

There is no information on the effect of gender on the pharmacokinetics of glipizide.

Metformin pharmacokinetic parameters did not differ significantly in subjects with or without type 2 diabetes when analyzed according to gender (males = 19, females = 16). Similarly, in controlled clinical studies in patients with type 2 diabetes, the antihyperglycemic effect of metformin was comparable in males and females.

Race

No information is available on race differences in the pharmacokinetics of glipizide.

No studies of metformin pharmacokinetic parameters according to race have been performed. In controlled clinical studies of metformin in patients with type 2 diabetes, the antihyperglycemic effect was comparable in whites (n = 249), blacks (n = 51), and Hispanics (n = 24).

Patients with Inadequate Glycemic Control on Diet and Exercise Alone

In a 24 week, double-blind, active-controlled, multicenter international clinical trial, patients with type 2 diabetes, whose hyperglycemia was not adequately controlled with diet and exercise alone (hemoglobin A 1c [HbA 1c] > 7.5% and ≤ 12%, and fasting plasma glucose [FPG] < 300 mg/dL) were randomized to receive initial therapy with glipizide 5 mg, metformin 500 mg, glipizide and metformin hydrochloride tablets, 2.5 mg/250 mg, or glipizide and metformin hydrochloride tablets, 2.5 mg/500 mg. After 2 weeks, the dose was progressively increased (up to the 12 week visit) to a maximum of 4 tablets daily in divided doses as needed to reach a target mean daily glucose (MDG) of ≤ 130 mg/dL. Trial data at 24 weeks are summarized in Table 2.

After 24 weeks, treatment with glipizide and metformin hydrochloride tablets, 2.5 mg/250 mg and 2.5 mg/500 mg resulted in significantly greater reduction in HbA 1c compared to glipizide and metformin therapy. Also, glipizide and metformin hydrochloride tablet, 2.5 mg/250 mg therapy resulted in significant reductions in FPG versus metformin therapy.

Increases above fasting glucose and insulin levels were determined at baseline and final study visits by measurement of plasma glucose and insulin for 3 hours following a standard mixed liquid meal. Treatment with glipizide and metformin hydrochloride tablets lowered the 3 hour postprandial glucose AUC, compared to baseline, to a significantly greater extent than did the glipizide and the metformin therapies. Compared to baseline, glipizide and metformin hydrochloride tablets enhanced the postprandial insulin response, but did not significantly affect fasting insulin levels.

There were no clinically meaningful differences in changes from baseline for all lipid parameters between glipizide and metformin hydrochloride tablet therapy and either metformin therapy or glipizide therapy. The adjusted mean changes from baseline in body weight were: glipizide and metformin hydrochloride tablets, 2.5 mg/250 mg, -0.4 kg; glipizide and metformin hydrochloride tablets, 2.5 mg/500 mg, -0.5 kg; glipizide, -0.2 kg; and metformin, -1.9 kg. Weight loss was greater with metformin than with glipizide and metformin hydrochloride tablets.

Patients with Inadequate Glycemic Control on Sulfonylurea Monotherapy

In an 18-week, double-blind, active-controlled U.S. clinical trial, a total of 247 patients with type 2 diabetes not adequately controlled (HbA 1c ≥ 7.5% and ≤ 12%, and FPG < 300 mg/dL) while being treated with at least one-half the maximum labeled dose of a sulfonylurea (e.g., glyburide 10 mg, glipizide 20 mg) were randomized to receive glipizide (fixed dose, 30 mg), metformin (500 mg), or glipizide and metformin hydrochloride tablets, 5 mg/500 mg. The doses of metformin and glipizide and metformin hydrochloride tablets were titrated (up to the 8 week visit) to a maximum of 4 tablets daily as needed to achieve MDG ≤ 130 mg/dL. Trial data at 18 weeks are summarized in Table 3.

After 18 weeks, treatment with glipizide and metformin hydrochloride tablets at doses up to 20 mg/2000 mg per day resulted in significantly lower mean final HbA 1c and significantly greater mean reductions in FPG compared to glipizide and metformin therapy. Treatment with glipizide and metformin hydrochloride tablets lowered the 3 hour postprandial glucose AUC, compared to baseline, to a significantly greater extent than did the glipizide and the metformin therapies. Glipizide and metformin hydrochloride tablets did not significantly affect fasting insulin levels.

There were no clinically meaningful differences in changes from baseline for all lipid parameters between glipizide and metformin hydrochloride tablet therapy and either metformin therapy or glipizide therapy. The adjusted mean changes from baseline in body weight were: glipizide and metformin hydrochloride tablets, 5 mg/500 mg, -0.3 kg; glipizide, -0.4 kg; and metformin, -2.7 kg. Weight loss was greater with metformin than with glipizide and metformin hydrochloride tablets.

Glipizide and Metformin Hydrochloride Tablets

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 increases 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 glipizide and metformin hydrochloride tablets. In glipizide and metformin hydrochloride tablet-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 glipizide 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 patients renal function include (see DOSAGE AND ADMINISTRATION, CLINICAL PHARMACOLOGY):
  • Before initiating glipizide and metformin hydrochloride tablets, obtain an estimated glomerular filtration rate (eGFR)
  • Glipizide and metformin hydrochloride tablets are contraindicated in patients with an eGFR less than 30 mL/min/1.73 m 2. Initiation of glipizide and metformin hydrochloride tablets is not recommended in patients with eGFR between 30 to 45 mL/min/1.73 m 2 (see CONTRAINDICATIONS).
  • Obtain an eGFR at least annually in all patients taking glipizide and metfomin hydrochloride tablets. In patients at risk for the development of renal impairment (e.g., the elderly), renal function should be assessed more frequently.
  • In patients taking glipizide and metformin hydrochloride tablets whose eGFR falls below 45 mL/min/1.73 m 2, assess the benefit and risk of continuing therapy.
• Drug interactions—The concomitant use of glipizide and metformin hydrochloride tablets 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 glipizide and metformin hydrochloride tablets 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 m 2; in patients with a history of hepatic impairment, alcoholism or heart failure, or in patients who will be administered intra-arterial iodinated contrast. Re-evaluate eGFR 48 hours after the imagining procedure, and restart glipizide and metformin hydrochloride tablets 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. Glipizide and metformin hydrochloride tablets 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 glipizide and metformin hydrochloride tablets.
• 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 glipizide and metformin hydrochloride tablets.
• 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 glipizide and metformin hydrochloride tablets in patients with clinical or laboratory evidence of hepatic disease.

Glipizide

Glipizide and Metformin Hydrochloride Tablets

Patients should be informed of the potential risks and benefits of glipizide and metformin hydrochloride tablets 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 glipizide and metformin hydrochloride tablets 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 glipizide and metformin hydrochloride tablets, 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 glipizide and metformin hydrochloride tablets (see PATIENT INFORMATION printed below).

Glipizide and Metformin Hydrochloride Tablets

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 glipizide and metformin hydrochloride tablets, the patient should be closely observed for loss of blood glucose control. When such drugs are withdrawn from a patient receiving glipizide and metformin hydrochloride tablets, 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.

Glipizide

The hypoglycemic action of sulfonylureas may be potentiated by certain drugs, including non-steroidal anti-inflammatory agents, some azoles, 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 glipizide and metformin hydrochloride tablets, the patient should be observed closely for hypoglycemia. When such drugs are withdrawn from a patient receiving glipizide and metformin hydrochloride tablets, the patient should be observed closely for loss of blood glucose control. In vitro binding studies with human serum proteins indicate that glipizide binds differently than tolbutamide and does not interact with salicylate or dicumarol. However, caution must be exercised in extrapolating these findings to the clinical situation and in the use of glipizide and metformin hydrochloride tablets with these drugs.

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. The effect of concomitant administration of fluconazole and glipizide has been demonstrated in a placebo-controlled crossover study in normal volunteers. All subjects received glipizide alone and following treatment with 100 mg of fluconazole as a single oral daily dose for 7 days, the mean percent increase in the glipizide AUC after fluconazole administration was 56.9% (range: 35% to 81%).

In studies assessing the effect of colesevelam on the pharmacokinetics of glipizide ER in healthy volunteers, reductions in glipizide AUC 0-∞ and C max of 12% and 13%, respectively, were observed when colesevelam was coadministered with glipizide ER. When glipizide ER was administered 4 hours prior to colesevelam, there was no significant change in glipizide AUC 0-∞ or C max, –4% and 0%, respectively. Therefore, glipizide and metformin hydrochloride tablets should be administered at least 4 hours prior to colesevelam to ensure that colesevelam does not reduce the absorption of glipizide.

Metformin Hydrochloride

Glipizide

A 20-month study in rats and an 18-month study in mice at doses up to 75 times the maximum human dose revealed no evidence of drug-related carcinogenicity. Bacterial and in vivo mutagenicity tests were uniformly negative. Studies in rats of both sexes at doses up to 75 times the human dose showed no effects on fertility.

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 4 times the maximum recommended human daily (MRHD) dose of 2000 mg of the metformin component of glipizide and metformin hydrochloride tablets 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 3 times the MRHD dose of the metformin component of glipizide and metformin hydrochloride tablets based on body surface area comparisons.

Teratogenic Effects: Pregnancy Category C

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, glipizide and metformin hydrochloride tablets should not be used during pregnancy unless clearly needed (see below).

There are no adequate and well-controlled studies in pregnant women with glipizide and metformin hydrochloride tablets or their individual components. No animal studies have been conducted with the combined products in glipizide and metformin hydrochloride tablets. The following data are based on findings in studies performed with the individual products.

Glipizide

Glipizide was found to be mildly fetotoxic in rat reproductive studies at all dose levels (5 to 50 mg/kg). This fetotoxicity has been similarly noted with other sulfonylureas, such as tolbutamide and tolazamide. The effect is perinatal and believed to be directly related to the pharmacologic (hypoglycemic) action of glipizide. In studies in rats and rabbits, no teratogenic effects were found.

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 2 and 6 times the MRHD dose of 2000 mg of the metformin component of glipizide and metformin hydrochloride tablets 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 glipizide and metformin hydrochloride tablets be used during pregnancy. However, if they are used, glipizide and metformin hydrochloride tablets should be discontinued at least 1 month before the expected delivery date (see Pregnancy, Teratogenic Effects: Pregnancy Category C).

Hypoglycemia

In a controlled initial therapy trial of glipizide and metformin hydrochloride tablets, 2.5 mg/250 mg and 2.5 mg/500 mg the numbers of patients with hypoglycemia documented by symptoms (such as dizziness, shakiness, sweating, and hunger) and a fingerstick blood glucose measurement ≤ 50 mg/dL were 5 (2.9%) for glipizide, 0 (0%) for metformin, 13 (7.6%) for glipizide and metformin hydrochloride tablets, 2.5 mg/250 mg, and 16 (9.3%) for glipizide and metformin hydrochloride tablets, 2.5 mg/500 mg. Among patients taking either glipizide and metformin hydrochloride tablets, 2.5 mg/250 mg or glipizide and metformin hydrochloride tablets, 2.5 mg/500 mg, 9 (2.6%) patients discontinued glipizide and metformin hydrochloride tablets due to hypoglycemic symptoms and 1 required medical intervention due to hypoglycemia. In a controlled second-line therapy trial of glipizide and metformin hydrochloride tablets, 5 mg/500 mg, the numbers of patients with hypoglycemia documented by symptoms and a fingerstick blood glucose measurement ≤ 50 mg/dL were 0 (0%) for glipizide, 1 (1.3%) for metformin, and 11 (12.6%) for glipizide and metformin hydrochloride tablets. One (1.1%) patient discontinued glipizide and metformin hydrochloride tablet therapy due to hypoglycemic symptoms and none required medical intervention due to hypoglycemia (see PRECAUTIONS).

Gastrointestinal Reactions

Among the most common clinical adverse events in the initial therapy trial were diarrhea and nausea/vomiting; the incidences of these events were lower with both glipizide and metformin hydrochloride tablets dosage strengths than with metformin therapy. There were 4 (1.2%) patients in the initial therapy trial who discontinued glipizide and metformin hydrochloride tablet therapy due to gastrointestinal (GI) adverse events. Gastrointestinal symptoms of diarrhea, nausea/vomiting, and abdominal pain were comparable among glipizide and metformin hydrochloride tablets, glipizide and metformin in the second-line therapy trial. There were 4 (4.6%) patients in the second-line therapy trial who discontinued glipizide and metformin hydrochloride tablet therapy due to GI adverse events.

Gastrointestinal Reactions

Cholestatic and hepatocellular forms of liver injury accompanied by jaundice have been reported rarely in association with glipizide; glipizide and metformin hydrochloride tablets should be discontinued if this occurs.