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GLUCOPHAGE®
(metformin hydrochloride) tablets, for oral use
GLUCOPHAGE®
(metformin hydrochloride) extended-release tablets, for oral use
WARNING
LACTIC ACIDOSIS
Postmarketing cases of metformin-associated lactic acidosis have resulted in death, hypothermia, hypotension, and resistant bradyarrhythmias. The onset of metforminassociated lactic acidosis is often subtle, accompanied only by nonspecific symptoms such as malaise, myalgias, respiratory distress, somnolence, and abdominal pain. Metforminassociated 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 WARNINGS AND 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, WARNINGS AND PRECAUTIONS].
If metformin-associated lactic acidosis is suspected, immediately discontinue GLUCOPHAGE or GLUCOPHAGE XR and institute general supportive measures in a hospital setting. Prompt hemodialysis is recommended [see WARNINGS AND PRECAUTIONS].
GLUCOPHAGE/GLUCOPHAGE XR contain the antihyperglycemic agent metformin, which is a biguanide, in the form of monohydrochloride. The chemical name of metformin hydrochloride is N,N-dimethylimidodicarbonimidic diamide hydrochloride. The structural formula is as shown below:
 |
Metformin hydrochloride is a white to off-white crystalline compound with a molecular formula of C4H11N5 • HCl and a molecular weight of 165.63. It is freely soluble in water and is practically insoluble in acetone, ether, and chloroform. The pKa of metformin is 12.4. The pH of a 1% aqueous solution of metformin hydrochloride is 6.68.
GLUCOPHAGE tablets contain 500 mg, 850 mg, or 1000 mg of metformin hydrochloride, which is equivalent to 389.93 mg, 662.88 mg, 779.86 mg metformin base, respectively. Each tablet contains the inactive ingredients povidone and magnesium stearate. In addition, the coating for the 500 mg and 850 mg tablets contains hypromellose and the coating for the 1000 mg tablet contains hypromellose and polyethylene glycol.
GLUCOPHAGE XR contains 500 mg or 750 mg of metformin hydrochloride, which is equivalent to 389.93 mg, 584.90 mg metformin base, respectively.
GLUCOPHAGE XR 500 mg tablets contain the inactive ingredients hypromellose, microcrystalline cellulose, sodium carboxymethyl cellulose, and magnesium stearate.
GLUCOPHAGE XR 750 mg tablets contain the inactive ingredients hypromellose, sodium carboxymethyl cellulose, magnesium stearate and iron oxide pigment red.
GLUCOPHAGE is indicated as an adjunct to diet and exercise to improve glycemic control in adults and pediatric patients 10 years of age and older with type 2 diabetes mellitus.
GLUCOPHAGE XR is indicated as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus.
Discontinue GLUCOPHAGE/GLUCOPHAGE XR at the time of, or prior to, an iodinated contrast imaging procedure in patients with an eGFR between 30 and 60 mL/min/1.73 m2; in patients with a history of 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 GLUCOPHAGE/GLUCOPHAGE XR if renal function is stable.
GLUCOPHAGE is available as:
GLUCOPHAGE XR is available as:
Table 13: GLUCOPHAGE/GLUCOPHAGE XR Available Strengths, Units, and Appearance
| GLUCOPHAGE Tablets | |||
| 500 mg | Bottles of 100 | NDC 0087-606005 | round, white to off-white, film-coated debossed with "BMS 6060" around the periphery on one side and "500" debossed across the face of the other side |
| Bottles of 500 | NDC 0087-606010 | ||
| 850 mg | Bottles of 100 | NDC 0087-607005 | round, white to off-white, film-coated debossed with "BMS 6070" around the periphery on one side and "850" debossed across the face of the other side |
| 1000 mg | Bottles of 100 | NDC 0087-607111 | white, oval, biconvex, film-coated with "BMS 6071" debossed on one side and "1000" debossed on the opposite side and with a bisect line on both sides |
| GLUCOPHAGE XR Extended-Release Tablets | |||
| 500 mg | Bottles of 100 | NDC 0087-606313 | white to off-white, capsule shaped, biconvex, with "BMS 6063" debossed on one side and "500" debossed across the face of the other side |
| 750 mg | Bottles of 100 | NDC 0087-606413 | pale red and may have a mottled appearance, capsule shaped, biconvex, with "BMS 6064" debossed on one side and "750" debossed on the other side |
Store at 20°–25°C (68°–77°F); excursions permitted to 15°–30°C (59°–86°F). [See USP Controlled Room Temperature.]
Dispense in light-resistant containers.
Distributed by: Bristol-Myers Squibb Company Princeton, NJ 08543 USA. Revised: May 2018.
The following adverse reactions are also discussed elsewhere in the labeling:
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
In a U.S. clinical trial of GLUCOPHAGE in patients with type 2 diabetes mellitus, a total of 141 patients received GLUCOPHAGE up to 2550 mg per day. Adverse reactions reported in greater than 5% of GLUCOPHAGE treated patients and that were more common than in placebo-treated patients, are listed in Table 1.
Table 1: Adverse Reactions from a Clinical Trial of GLUCOPHAGE Occurring >5% and More Common than Placebo in Patients with Type 2 Diabetes Mellitus
| GLUCOPHAGE (n=141) |
Placebo (n=145) |
|
| Diarrhea | 53% | 12% |
| Nausea/Vomiting | 26% | 8% |
| Flatulence | 12% | 6% |
| Asthenia | 9% | 6% |
| Indigestion | 7% | 4% |
| Abdominal Discomfort | 6% | 5% |
| Headache | 6% | 5% |
Diarrhea led to discontinuation of GLUCOPHAGE in 6% of patients. Additionally, the following adverse reactions were reported in ≥1% to ≤5% of GLUCOPHAGE treated patients and were more commonly reported with GLUCOPHAGE than placebo: abnormal stools, hypoglycemia, myalgia, lightheaded, dyspnea, nail disorder, rash, sweating increased, taste disorder, chest discomfort, chills, flu syndrome, flushing, palpitation.
In GLUCOPHAGE clinical trials of 29-week duration, a decrease to subnormal levels of previously normal serum vitamin B12 levels was observed in approximately 7% of patients.
Pediatric Patients
In clinical trials with GLUCOPHAGE in pediatric patients with type 2 diabetes mellitus, the profile of adverse reactions was similar to that observed in adults.
In placebo-controlled trials, 781 patients were administered GLUCOPHAGE XR. Adverse reactions reported in greater than 5% of the GLUCOPHAGE XR patients, and that were more common in GLUCOPHAGE XR-than placebo-treated patients, are listed in Table 2.
Table 2: Adverse Reactions from Clinical Trials of GLUCOPHAGE XR Occurring >5% and More Common than Placebo in Patients with Type 2 Diabetes Mellitus
| GLUCOPHAGE XR (n=781) |
Placebo (n=195) |
|
| Diarrhea | 10% | 3% |
| Nausea/Vomiting | 7% | 2% |
Diarrhea led to discontinuation of GLUCOPHAGE XR in 0.6% of patients. Additionally, the following adverse reactions were reported in ≥1.0% to ≤5.0% of GLUCOPHAGE XR patients and were more commonly reported with GLUCOPHAGE XR than placebo: abdominal pain, constipation, distention abdomen, dyspepsia/heartburn, flatulence, dizziness, headache, upper respiratory infection, taste disturbance.
The following adverse reactions have been identified during post approval use of metformin. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Cholestatic, hepatocellular, and mixed hepatocellular liver injury have been reported with postmarketing use of metformin.
Table 3 presents clinically significant drug interactions with GLUCOPHAGE/GLUCOPHAGE XR.
Table 3: Clinically Significant Drug Interactions with GLUCOPHAGE/GLUCOPHAGE XR
| Carbonic Anhydrase Inhibitors | |
| Clinical Impact: | Carbonic anhydrase inhibitors frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of these drugs with GLUCOPHAGE/GLUCOPHAGE XR may increase the risk for lactic acidosis. |
| Intervention: | Consider more frequent monitoring of these patients. |
| Examples: | Topiramate, zonisamide, acetazolamide or dichlorphenamide. |
| Drugs that Reduce GLUCOPHAGE/GLUCOPHAGE XR Clearance | |
| Clinical Impact: | Concomitant use of drugs that interfere with common renal tubular transport systems involved in the renal elimination of metformin (e.g., organic cationic transporter-2 [OCT2] / multidrug and toxin extrusion [MATE] inhibitors) could increase systemic exposure to metformin and may increase the risk for lactic acidosis [see CLINICAL PHARMACOLOGY]. |
| Intervention: | Consider the benefits and risks of concomitant use with GLUCOPHAGE/GLUCOPHAGE XR. |
| Examples: | Ranolazine, vandetanib, dolutegravir, and cimetidine. |
| Alcohol | |
| Clinical Impact: | Alcohol is known to potentiate the effect of metformin on lactate metabolism. |
| Intervention: | Warn patients against excessive alcohol intake while receiving GLUCOPHAGE/GLUCOPHAGE XR. |
| Insulin Secretagogues or Insulin | |
| Clinical Impact: | Coadministration of GLUCOPHAGE/GLUCOPHAGE XR with an insulin secretagogue (e.g., sulfonylurea) or insulin may increase the risk of hypoglycemia. |
| Intervention: | Patients receiving an insulin secretagogue or insulin may require lower doses of the insulin secretagogue or insulin. |
| Drugs Affecting Glycemic Control | |
| Clinical Impact: | Certain drugs tend to produce hyperglycemia and may lead to loss of glycemic control. |
| Intervention: | When such drugs are administered to a patient receiving GLUCOPHAGE/GLUCOPHAGE XR, observe the patient closely for loss of blood glucose control. When such drugs are withdrawn from a patient receiving GLUCOPHAGE/GLUCOPHAGE XR, observe the patient closely for hypoglycemia. |
| Examples: | Thiazides and other diuretics, corticosteroids, phenothiazines, thyroid products, estrogens, oral contraceptives, phenytoin, nicotinic acid, sympathomimetics, calcium channel blockers, and isoniazid. |
Included as part of the "PRECAUTIONS" Section
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. Metforminassociated 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 GLUCOPHAGE/GLUCOPHAGE XR. In GLUCOPHAGE/GLUCOPHAGE XR 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 GLUCOPHAGE/GLUCOPHAGE XR 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:
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]:
In GLUCOPHAGE clinical trials of 29-week duration, a decrease to subnormal levels of previously normal serum vitamin B12 levels was observed in approximately 7% of patients. Such decrease, possibly due to interference with B12 absorption from the B12-intrinsic factor complex, may be associated with anemia but appears to be rapidly reversible with discontinuation of GLUCOPHAGE or vitamin B12 supplementation. Certain individuals (those with inadequate vitamin B12 or calcium intake or absorption) appear to be predisposed to developing subnormal vitamin B12 levels. Measure hematologic parameters on an annual basis and vitamin B12 at 2 to 3 year intervals in patients on GLUCOPHAGE/GLUCOPHAGE XR and manage any abnormalities [see ADVERSE REACTIONS].
Insulin and insulin secretagogues (e.g., sulfonylurea) are known to cause hypoglycemia. GLUCOPHAGE/GLUCOPHAGE XR may increase the risk of hypoglycemia when combined with insulin and/or an insulin secretagogue. Therefore, a lower dose of insulin or insulin secretagogue may be required to minimize the risk of hypoglycemia when used in combination with GLUCOPHAGE/GLUCOPHAGE XR [see DRUG INTERACTIONS].
There have been no clinical studies establishing conclusive evidence of macrovascular risk reduction with GLUCOPHAGE/GLUCOPHAGE XR.
Advise the patient to read the FDA-approved patient labeling (PATIENT INFORMATION).
Explain the risks of lactic acidosis, its symptoms, and conditions that predispose to its development. Advise patients to discontinue GLUCOPHAGE/GLUCOPHAGE XR immediately and to promptly notify their healthcare provider if unexplained hyperventilation, myalgias, malaise, unusual somnolence or other nonspecific symptoms occur. Counsel patients against excessive alcohol intake and inform patients about importance of regular testing of renal function while receiving GLUCOPHAGE/GLUCOPHAGE XR. Instruct patients to inform their doctor that they are taking GLUCOPHAGE/GLUCOPHAGE XR prior to any surgical or radiological procedure, as temporary discontinuation may be required [see WARNINGS AND PRECAUTIONS].
Inform patients that hypoglycemia may occur when GLUCOPHAGE/GLUCOPHAGE XR is coadministered with oral sulfonylureas and insulin. Explain to patients receiving concomitant therapy the risks of hypoglycemia, its symptoms and treatment, and conditions that predispose to its development [see WARNINGS AND PRECAUTIONS].
Inform patients about importance of regular hematological parameters while receiving GLUCOPHAGE/GLUCOPHAGE XR [see WARNINGS AND PRECAUTIONS].
Inform females that treatment with GLUCOPHAGE/GLUCOPHAGE XR may result in ovulation in some premenopausal anovulatory women which may lead to unintended pregnancy [see Use In Specific Populations].
Inform patients that GLUCOPHAGE XR must be swallowed whole and not crushed, cut, or chewed, and that the inactive ingredients may occasionally be eliminated in the feces as a soft mass that may resemble the original tablet.
Long-term carcinogenicity studies have been performed 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 3 times the maximum recommended human daily dose of 2550 mg based on body surface area comparisons. No evidence of carcinogenicity with metformin was found in either male or female mice. Similarly, there was no tumorigenic potential observed with metformin in male rats. There was, however, an increased incidence of benign stromal uterine polyps in female rats treated with 900 mg/kg/day.
There was no evidence of a mutagenic potential of metformin 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 when administered at doses as high as 600 mg/kg/day, which is approximately 2 times the maximum recommended human daily dose of 2550 mg based on body surface area comparisons.
Limited data with GLUCOPHAGE/GLUCOPHAGE XR in pregnant women are not sufficient to determine a drug-associated risk for major birth defects or miscarriage. Published studies with metformin use during pregnancy have not reported a clear association with metformin and major birth defect or miscarriage risk [see Data]. There are risks to the mother and fetus associated with poorly controlled diabetes mellitus in pregnancy [see Clinical Considerations].
No adverse developmental effects were observed when metformin was administered to pregnant Sprague Dawley rats and rabbits during the period of organogenesis at doses up to 2-and 5times, respectively, a 2550 mg clinical dose, based on body surface area [see Data].
The estimated background risk of major birth defects is 6–10% in women with pre-gestational diabetes mellitus with an HbA1C >7 and has been reported to be as high as 20–25% in women with a HbA1C >10. The estimated background risk of miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2–4% and 15–20%, respectively.
Disease-associated Maternal and/or Embryo/fetal Risk
Poorly-controlled diabetes mellitus in pregnancy increases the maternal risk for diabetic ketoacidosis, pre-eclampsia, spontaneous abortions, preterm delivery, stillbirth and delivery complications. Poorly controlled diabetes mellitus increases the fetal risk for major birth defects, stillbirth, and macrosomia related morbidity.
Human Data
Published data from post-marketing studies have not reported a clear association with metformin and major birth defects, miscarriage, or adverse maternal or fetal outcomes when metformin was used during pregnancy. However, these studies cannot definitely establish the absence of any metformin-associated risk because of methodological limitations, including small sample size and inconsistent comparator groups.
Animal Data
Metformin hydrochloride did not adversely affect development outcomes when administered to pregnant rats and rabbits at doses up to 600 mg/kg/day. This represents an exposure of about 2 and 5 times a 2550 mg clinical dose based on body surface area comparisons for rats and rabbits, respectively. Determination of fetal concentrations demonstrated a partial placental barrier to metformin.
Limited published studies report that metformin is present in human milk [see Data]. However, there is insufficient information to determine the effects of metformin on the breastfed infant and no available information on the effects of metformin on milk production. Therefore, the developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for GLUCOPHAGE/GLUCOPHAGE XR and any potential adverse effects on the breastfed child from GLUCOPHAGE/GLUCOPHAGE XR or from the underlying maternal condition.
Published clinical lactation studies report that metformin is present in human milk which resulted in infant doses approximately 0.11% to 1% of the maternal weight-adjusted dosage and a milk/plasma ratio ranging between 0.13 and 1. However, the studies were not designed to definitely establish the risk of use of metformin during lactation because of small sample size and limited adverse event data collected in infants.
Discuss the potential for unintended pregnancy with premenopausal women as therapy with GLUCOPHAGE/GLUCOPHAGE XR may result in ovulation in some anovulatory women.
The safety and effectiveness of GLUCOPHAGE for the treatment of type 2 diabetes mellitus have been established in pediatric patients 10 to 16 years old. Safety and effectiveness of GLUCOPHAGE have not been established in pediatric patients less than 10 years old.
Use of GLUCOPHAGE in pediatric patients 10 to 16 years old for the treatment of type 2 diabetes mellitus is supported by evidence from adequate and well-controlled studies of GLUCOPHAGE in adults with additional data from a controlled clinical study in pediatric patients 10 to 16 years old with type 2 diabetes mellitus, which demonstrated a similar response in glycemic control to that seen in adults [see Clinical Studies]. In this study, adverse reactions were similar to those described in adults. A maximum daily dose of 2000 mg of GLUCOPHAGE is recommended. [See DOSAGE AND ADMINISTRATION.]
Safety and effectiveness of GLUCOPHAGE XR in pediatric patients have not been established.
Controlled clinical studies of GLUCOPHAGE/GLUCOPHAGE XR did not include sufficient numbers of elderly patients to determine whether they respond differently from younger patients. 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 WARNINGS AND PRECAUTIONS].
Metformin is substantially excreted by the kidney, and the risk of metformin accumulation and lactic acidosis increases with the degree of renal impairment. GLUCOPHAGE/GLUCOPHAGE XR is contraindicated in severe renal impairment, patients with an estimated glomerular filtration rate (eGFR) below 30 mL/min/1.73 m2 [see DOSAGE AND ADMINISTRATION, CONTRAINDICATIONS, WARNINGS AND PRECAUTIONS, and CLINICAL PHARMACOLOGY].
Use of metformin in patients with hepatic impairment has been associated with some cases of lactic acidosis. GLUCOPHAGE/GLUCOPHAGE XR is not recommended in patients with hepatic impairment. [see WARNINGS AND PRECAUTIONS].
Overdose of metformin hydrochloride has occurred, including ingestion of amounts greater than 50 grams. Hypoglycemia was reported in approximately 10% of cases, but no causal association with metformin has been established. Lactic acidosis has been reported in approximately 32% of metformin overdose cases [see WARNINGS AND PRECAUTIONS]. Metformin is dialyzable with a clearance of up to 170 mL/min under good hemodynamic conditions. Therefore, hemodialysis may be useful for removal of accumulated drug from patients in whom metformin overdosage is suspected.
GLUCOPHAGE and GLUCOPHAGE XR are contraindicated in patients with:
Metformin is an antihyperglycemic agent which improves glucose tolerance in patients with type 2 diabetes mellitus, lowering both basal and postprandial plasma glucose. Metformin decreases hepatic glucose production, decreases intestinal absorption of glucose, and improves insulin sensitivity by increasing peripheral glucose uptake and utilization. With metformin therapy, insulin secretion remains unchanged while fasting insulin levels and day-long plasma insulin response may decrease.
The absolute bioavailability of a GLUCOPHAGE 500 mg tablet given under fasting conditions is approximately 50% to 60%. Studies using single oral doses of GLUCOPHAGE 500 to 1500 mg and 850 to 2550 mg, indicate that there is a lack of dose proportionality with increasing doses, which is due to decreased absorption rather than an alteration in elimination. At usual clinical doses and dosing schedules of GLUCOPHAGE, steady state plasma concentrations of metformin are reached within 24 to 48 hours and are generally <1 μg/mL.
Following a single oral dose of GLUCOPHAGE XR, Cmax is achieved with a median value of 7 hours and a range of 4 to 8 hours. Peak plasma levels are approximately 20% lower compared to the same dose of GLUCOPHAGE, however, the extent of absorption (as measured by AUC) is comparable to GLUCOPHAGE.
At steady state, the AUC and Cmax are less than dose proportional for GLUCOPHAGE XR within the range of 500 to 2000 mg administered once daily. Peak plasma levels are approximately 0.6, 1.1, 1.4 and 1.8 mcg/mL for 500, 1000, 1500, and 2000 mg once-daily doses, respectively. The extent of metformin absorption (as measured by AUC) from GLUCOPHAGE XR at a 2000 mg once-daily dose is similar to the same total daily dose administered as GLUCOPHAGE tablets 1000 mg twice daily. After repeated administration of GLUCOPHAGE XR, metformin did not accumulate in plasma.
Effect of food:
Food decreases the extent of absorption and slightly delays the absorption of metformin, as shown by approximately a 40% lower mean peak plasma concentration (Cmax), a 25% lower area under the plasma concentration versus time curve (AUC), and a 35-minute prolongation of time to peak plasma concentration (Tmax) following administration of a single 850 mg tablet of GLUCOPHAGE with food, compared to the same tablet strength administered fasting.
Although the extent of metformin absorption (as measured by AUC) from the GLUCOPHAGE XR tablet increased by approximately 50% when given with food, there was no effect of food on Cmax and Tmax of metformin. Both high and low fat meals had the same effect on the pharmacokinetics of GLUCOPHAGE XR.
The apparent volume of distribution (V/F) of metformin following single oral doses of GLUCOPHAGE 850 mg averaged 654 ± 358 L. Metformin is negligibly bound to plasma proteins. Metformin partitions into erythrocytes, most likely as a function of time.
Intravenous single-dose studies in normal subjects demonstrate that metformin is excreted unchanged in the urine and does not undergo hepatic metabolism (no metabolites have been identified in humans) nor biliary excretion.
Renal clearance (see Table 4) is approximately 3.5 times greater than creatinine clearance, which indicates that tubular secretion is the major route of metformin elimination. Following oral administration, approximately 90% of the absorbed drug is eliminated via the renal route within the first 24 hours, with a plasma elimination half-life of approximately 6.2 hours. In blood, the elimination half-life is approximately 17.6 hours, suggesting that the erythrocyte mass may be a compartment of distribution.
In patients with decreased renal function the plasma and blood half-life of metformin is prolonged and the renal clearance is decreased (see Table 3) [See DOSAGE AND ADMINISTRATION, CONTRAINDICATIONS, WARNINGS AND PRECAUTIONS and Use In Specific Populations].
No pharmacokinetic studies of metformin have been conducted in patients with hepatic impairment [See WARNINGS AND PRECAUTIONS and Use In Specific Populations].
Limited data from controlled pharmacokinetic studies of GLUCOPHAGE in healthy elderly subjects suggest that total plasma clearance of metformin is decreased, the half-life is prolonged, and Cmax is increased, compared to healthy young subjects. It appears that the change in metformin pharmacokinetics with aging is primarily accounted for by a change in renal function (see Table 4). [See WARNINGS AND PRECAUTIONS and Use In Specific Populations].
Table 4: Select Mean (±S.D.) Metformin Pharmacokinetic Parameters Following Single or Multiple Oral Doses of GLUCOPHAGE
| Subject Groups: GLUCOPHAGE dosea (number of subjects) | Cmax b (mcg/mL) |
Tmax c (hrs) |
Renal Clearance (mL/min) |
| Healthy, nondiabetic adults: | |||
| 500 mg single dose (24) | 1.03 (±0.33) | 2.75 (±0.81) | 600 (±132) |
| 850 mg single dose (74)d | 1.60 (±0.38) | 2.64 (±0.82) | 552 (±139) |
| 850 mg three times daily for 19 dosese (9) | 2.01 (±0.42) | 1.79 (±0.94) | 642 (±173) |
| Adults with type 2 diabetes mellitus: | |||
| 850 mg single dose (23) | 1.48 (±0.5) | 3.32 (±1.08) | 491 (±138) |
| 850 mg three times daily for 19 dosese (9) | 1.90 (±0.62) | 2.01 (±1.22) | 550 (±160) |
| Elderlyf, healthy nondiabetic adults: | |||
| 850 mg single dose (12) | 2.45 (±0.70) | 2.71 (±1.05) | 412 (±98) |
| Renal-impaired adults: | |||
| 850 mg single dose | |||
| Mild (CLcrg 61-90 mL/min) (5) | 1.86 (±0.52) | 3.20 (±0.45) | 384 (±122) |
| Moderate (CLcr 31-60 mL/min) (4) | 4.12 (±1.83) | 3.75 (±0.50) | 108 (±57) |
| Severe (CLcr 10-30 mL/min) (6) | 3.93 (±0.92) | 4.01 (±1.10) | 130 (±90) |
|
a All doses given fasting except the first 18 doses of the multiple dose studies b Peak plasma concentration c Time to peak plasma concentration d Combined results (average means) of five studies: mean age 32 years (range 23-59 years) e Kinetic study done following dose 19, given fasting f Elderly subjects, mean age 71 years (range 65-81 years) g CLcr = creatinine clearance normalized to body surface area of 1.73 m2 |
|||
After administration of a single oral GLUCOPHAGE 500 mg tablet with food, geometric mean metformin Cmax and AUC differed less than 5% between pediatric type 2 diabetic patients (12-16 years of age) and gender-and weight-matched healthy adults (20-45 years of age), all with normal renal function.
Metformin pharmacokinetic parameters did not differ significantly between normal subjects and patients with type 2 diabetes mellitus when analyzed according to gender (males=19, females=16).
No studies of metformin pharmacokinetic parameters according to race have been performed.
Table 5: Effect of Coadministered Drug on Plasma Metformin Systemic
Exposure
| Coadministered Drug | Dose of Coadministered Drug* | Dose of Metformin* | Geometric Mean Ratio (ratio with/without coadministered drug) No Effect = 1.00 |
||
| AUC† | Cmax | ||||
| No dosing adjustments required for the following: | |||||
| Glyburide | 5 mg | 850 mg | metformin | 0.91‡ | 0.93‡ |
| Furosemide | 40 mg | 850 mg | metformin | 1.09‡ | 1.22‡ |
| Nifedipine | 10 mg | 850 mg | metformin | 1.16 | 1.21 |
| Propranolol | 40 mg | 850 mg | metformin | 0.90 | 0.94 |
| Ibuprofen | 400 mg | 850 mg | metformin | 1.05‡ | 1.07‡ |
| Cationic drugs eliminated by renal tubular secretion may reduce metformin elimination [See WARNINGS AND PRECAUTIONS and DRUG INTERACTIONS] | |||||
| Cimetidine | 400 mg | 850 mg | metformin | 1.40 | 1.61 |
| Carbonic anhydrase inhibitors may cause metabolic acidosis [See WARNINGS AND PRECAUTIONS and DRUG INTERACTIONS .] | |||||
| Topiramate | 100 mg§ | 500 mg§ | metformin | 1.25§ | 1.17 |
| * All metformin and coadministered drugs were given as single doses † AUC = AUC(INF) ‡ Ratio of arithmetic means § At steady state with topiramate 100 mg every 12 hours and metformin 500 mg every 12 hours; AUC = AUC0-12h |
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Table 6: Effect of Metformin on Coadministered Drug Systemic Exposure
| Coadministered Drug | Dose of Coadministered Drug* | Dose of Metformin* | Geometric Mean Ratio (ratio with/without metformin) No Effect = 1.00 |
||
| AUC† | Cmax | ||||
| No dosing adjustments required for the following: | |||||
| Glyburide | 5 mg | 850 mg | glyburide | 0.78‡ | 0.63‡ |
| Furosemide | 40 mg | 850 mg | furosemide | 0.87‡ | 0.69‡ |
| Nifedipine | 10 mg | 850 mg | nifedipine | 1.10§ | 1.08 |
| Propranolol | 40 mg | 850 mg | propranolol | 1.01§ | 1.02 |
| Ibuprofen | 400 mg | 850 mg | ibuprofen | 0.97¶ | 1.01¶ |
| Cimetidine | 400 mg | 850 mg | cimetidine | 0.95§ | 1.01 |
| * All metformin and coadministered drugs were given as single doses † AUC = AUC(INF) unless otherwise noted ‡ Ratio of arithmetic means, p-value of difference <0.05 § AUC(0-24 hr) reported ¶ Ratio of arithmetic means |
|||||
A double-blind, placebo-controlled, multicenter US clinical trial involving obese patients with type 2 diabetes mellitus whose hyperglycemia was not adequately controlled with dietary management alone (baseline fasting plasma glucose [FPG] of approximately 240 mg/dL) was conducted. Patients were treated with GLUCOPHAGE (up to 2550 mg/day) or placebo for 29 weeks. The results are presented in Table 7.
Table 7: Mean Change in Fasting Plasma Glucose and HbA1c at Week 29 Comparing GLUCOPHAGE vs Placebo in Patients with Type 2 Diabetes Mellitus
| GLUCOPHAGE (n=141) |
Placebo (n=145) |
p-Value | |
| FPG (mg/dL) | |||
| Baseline | 241.5 | 237.7 | NS* |
| Change at FINAL VISIT | –53.0 | 6.3 | 0.001 |
| Hemoglobin A1c (%) | |||
| Baseline | 8.4 | 8.2 | NS* |
| Change at FINAL VISIT | –1.4 | 0.4 | 0.001 |
| * Not statistically significant | |||
Mean baseline body weight was 201 lbs and 206 lbs in the GLUCOPHAGE and placebo arms, respectively. Mean change in body weight from baseline to week 29 was -1.4 lbs and -2.4 lbs in the GLUCOPHAGE and placebo arms, respectively.A 29-week, double-blind, placebo-controlled study of GLUCOPHAGE and glyburide, alone and in combination, was conducted in obese patients with type 2 diabetes mellitus who had failed to achieve adequate glycemic control while on maximum doses of glyburide (baseline FPG of approximately 250 mg/dL). Patients randomized to the combination arm started therapy with GLUCOPHAGE 500 mg and glyburide 20 mg. At the end of each week of the first 4 weeks of the trial, these patients had their dosages of GLUCOPHAGE increased by 500 mg if they had failed to reach target fasting plasma glucose. After week 4, such dosage adjustments were made monthly, although no patient was allowed to exceed GLUCOPHAGE 2500 mg. Patients in the GLUCOPHAGE only arm (metformin plus placebo) discontinued glyburide and followed the same titration schedule. Patients in the glyburide arm continued the same dose of glyburide. At the end of the trial, approximately 70% of the patients in the combination group were taking GLUCOPHAGE 2000 mg/glyburide 20 mg or GLUCOPHAGE 2500 mg/glyburide 20 mg. The results are displayed in Table 8.
Table 8: Mean Change in Fasting Plasma Glucose and HbA1c at Week 29 Comparing GLUCOPHAGE/Glyburide (Comb) vs Glyburide (Glyb) vs GLUCOPHAGE (GLU): in Patients with Type 2 Diabetes Mellitus with Inadequate Glycemic Control on Glyburide
| Comb (n=213) |
Glyb (n=209 ) |
GLU (n=210) |
p-Values | |||
| Glyb vs Comb | GLU vs Comb | GLU vs Glyb | ||||
| Fasting Plasma Glucose (mg/dL) | ||||||
| Baseline | 250.5 | 247.5 | 253.9 | NS* | NS* | NS* |
| Change at FINAL VISIT | –63.5 | 13.7 | –0.9 | 0.001 | 0.001 | 0.025 |
| Hemoglobin A1c (%) | ||||||
| Baseline | 8.8 | 8.5 | 8.9 | NS* | NS* | 0.007 |
| Change at FINAL VISIT | –1.7 | 0.2 | –0.4 | 0.001 | 0.001 | 0.001 |
| * Not statistically significant | ||||||
Mean baseline body weight was 202 lbs, 203 lbs, and 204 lbs in the GLUCOPHAGE/glyburide, glyburide, and GLUCOPHAGE arms, respectively. Mean change in body weight from baseline to week 29 was 0.9 lbs, -0.7 lbs, and -8.4 lbs in the GLUCOPHAGE/glyburide, glyburide, and GLUCOPHAGE arms, respectively.
A double-blind, placebo-controlled study in pediatric patients aged 10 to 16 years with type 2 diabetes mellitus (mean FPG 182.2 mg/dL), treatment with GLUCOPHAGE (up to 2000 mg/day) for up to 16 weeks (mean duration of treatment 11 weeks) was conducted. The results are displayed in Table 9.
Table 9: Mean Change in Fasting Plasma Glucose at Week 16 Comparing GLUCOPHAGE vs Placebo in Pediatric Patientsa with Type 2 Diabetes Mellitus
| GLUCOPHAGE | Placebo | p-Value | |
| FPG (mg/dL) | (n=37) | (n=36) | |
| Baseline | 162.4 | 192.3 | |
| Change at FINAL VISIT | –42.9 | 21.4 | <0.001 |
| a Pediatric patients mean age 13.8 years (range 10-16 years) | |||
Mean baseline body weight was 205 lbs and 189 lbs in the GLUCOPHAGE and placebo arms, respectively. Mean change in body weight from baseline to week 16 was -3.3 lbs and -2.0 lbs in the GLUCOPHAGE and placebo arms, respectively.
A 24-week, double-blind, placebo-controlled study of GLUCOPHAGE XR, taken once daily with the evening meal, was conducted in patients with type 2 diabetes mellitus who had failed to achieve glycemic control with diet and exercise. Patients entering the study had a mean baseline HbA1c of 8.0% and a mean baseline FPG of 176 mg/dL. The treatment dose was increased to 1500 mg once daily if at Week 12 HbA1c was ≥7.0% but <8.0% (patients with HbA1c ≥8.0% were discontinued from the study). At the final visit (24-week), mean HbA1c had increased 0.2% from baseline in placebo patients and decreased 0.6% with GLUCOPHAGE XR.
A 16-week, double-blind, placebo-controlled, dose-response study of GLUCOPHAGE XR, taken once daily with the evening meal or twice daily with meals, was conducted in patients with type 2 diabetes mellitus who had failed to achieve glycemic control with diet and exercise. The results are shown in Table 10.
Table 10: Mean Changes from Baseline* in HbA1c and Fasting Plasma Glucose at Week 16 Comparing GLUCOPHAGE XR vs Placebo in Patients with Type 2 Diabetes Mellitus
| GLUCOPHAGE XR | Placebo | |||||
| 500 mg Once Daily | 1000 mg Once Daily | 1500 mg Once Daily | 2000 mg Once Daily | 1000 mg Twice Daily | ||
| Hemoglobin A1c (%) | (n=115) | (n=115) | (n=111) | (n=125) | (n=112) | (n=111) |
| Baseline | 8.2 | 8.4 | 8.3 | 8.4 | 8.4 | 8.4 |
| Change at FINAL VISIT | –0.4 | –0.6 | –0.9 | –0.8 | –1.1 | 0.1 |
| p-valuea | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | – |
| FPG (mg/dL) | (n=126) | (n=118) | (n=120) | (n=132) | (n=122) | (n=113) |
| Baseline | 182.7 | 183.7 | 178.9 | 181.0 | 181.6 | 179.6 |
| Change at FINAL VISIT | –15.2 | –19.3 | –28.5 | –29.9 | –33.6 | 7.6 |
| p-valuea | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | – |
| a All comparisons versus Placebo | ||||||
Mean baseline body weight was 193 lbs, 192 lbs, 188 lbs, 196 lbs, 193 lbs and 194 lbs in the GLUCOPHAGE XR 500 mg , 1000 mg, 1500 mg, and 2000 mg once daily, 1000 mg twice daily and placebo arms, respectively. Mean change in body weight from baseline to week 16 was -1.3 lbs, -1.3 lbs, -0.7 lbs, -1.5 lbs, -2.2 lbs and -1.8 lbs, respectively.
A 24-week, double-blind, randomized study of GLUCOPHAGE XR, taken once daily with the evening meal, and GLUCOPHAGE, taken twice daily (with breakfast and evening meal), was conducted in patients with type 2 diabetes mellitus who had been treated with GLUCOPHAGE 500 mg twice daily for at least 8 weeks prior to study entry. The results are shown in Table 11.
Table 11: Mean Changes from Baseline* in HbA1c and Fasting Plasma Glucose at Week 24 Comparing GLUCOPHAGE XR vs GLUCOPHAGE in Patients with Type 2 Diabetes Mellitus
| GLUCOPHAGE 500 mg Twice Daily |
GLUCOPHAGE XR | ||
| 1000 mg Once Daily |
1500 mg Once Daily |
||
| Hemoglobin A1c (%) | (n=67) | (n=72) | (n=66) |
| Baseline | 7.06 | 6.99 | 7.02 |
| Change at FINAL VISIT (95% CI) |
0.14a (–0.04, 0.31) |
0.27 (0.11, 0.43) |
0.13 (–0.02, 0.28) |
| FPG (mg/dL) | (n=69) | (n=72) | (n=70) |
| Baseline | 127.2 | 131.0 | 131.4 |
| Change at FINAL VISIT (95% CI) |
14.0 (7.0, 21.0) |
11.5 (4.4, 18.6) |
7.6 (1.0, 14.2) |
| †a n=68 | |||
Mean baseline body weight was 210lbs, 203 lbs and 193 lbs in the GLUCOPHAGE 500mg twice daily, and GLUCOPHAGE XR 1000mg and 1500mg once daily arms, respectively. Mean change in body weight from baseline to week 24 was 0.9 lbs, 1.1 lbs and 0.9 lbs, respectively.
GLUCOPHAGE®
[gloo-ko-fahzh]
(metformin hydrochloride) Tablets
and
GLUCOPHAGE® XR
[gloo-ko-fahzh X-R]
(metformin hydrochloride)
Extended-Release Tablets
Read the Patient Information that comes with GLUCOPHAGE and GLUCOPHAGE XR before you start taking it and each time you get a refill. There may be new information. This leaflet does not take the place of talking with your healthcare provider about your medical condition or treatment.
What is the most important information I should know about GLUCOPHAGE and GLUCOPHAGE XR?
Serious side effects can happen in people taking GLUCOPHAGE or GLUCOPHAGE XR, including:
Lactic Acidosis. Metformin hydrochloride, the medicine in GLUCOPHAGE and GLUCOPHAGE XR, can cause a rare, but serious, side effect called lactic acidosis (a build-up of lactic acid in the blood) that can cause death. Lactic acidosis is a medical emergency and must be treated in a hospital.
Stop taking GLUCOPHAGE or GLUCOPHAGE XR and call your healthcare provider right away if you get any of the following symptoms of lactic acidosis:
You have a higher chance of getting lactic acidosis if you:
What are GLUCOPHAGE and GLUCOPHAGE XR?
GLUCOPHAGE and GLUCOPHAGE XR have the same active ingredient. However, GLUCOPHAGE XR works longer in your body. Both of these medicines help control your blood sugar in a number of ways. These include helping your body respond better to the insulin it makes naturally, decreasing the amount of sugar your liver makes, and decreasing the amount of sugar your intestines absorb. GLUCOPHAGE and GLUCOPHAGE XR do not cause your body to make more insulin.
Who should not take GLUCOPHAGE or GLUCOPHAGE XR?
Some conditions increase your chance of getting lactic acidosis, or cause other problems if you take either of these medicines. Most of the conditions listed below can increase your chance of getting lactic acidosis.
Do not take GLUCOPHAGE or GLUCOPHAGE XR if you:
What should I tell my healthcare provider before taking GLUCOPHAGE or GLUCOPHAGE XR?
Before taking GLUCOPHAGE or GLUCOPHAGE XR, tell your healthcare provider if you:
Tell your healthcare provider about all the medicines you take, including prescription and nonprescription medicines, vitamins, and herbal supplements. Know the medicines you take. Keep a list of them to show your healthcare provider and pharmacist when you get a new medicine.
Can GLUCOPHAGE or GLUCOPHAGE XR be used in children?
GLUCOPHAGE has been shown to effectively lower glucose levels in children (ages 10-16 years) with type 2 diabetes. GLUCOPHAGE has not been studied in children younger than 10 years old. GLUCOPHAGE has not been studied in combination with other oral glucose-control medicines or insulin in children. If you have any questions about the use of GLUCOPHAGE in children, talk with your doctor or other healthcare provider.
GLUCOPHAGE XR has not been studied in children.
How should I take GLUCOPHAGE or GLUCOPHAGE XR?
What should I avoid while taking GLUCOPHAGE or GLUCOPHAGE XR?
Do not drink a lot of alcoholic drinks while taking GLUCOPHAGE or GLUCOPHAGE XR. This means you should not binge drink for short periods, and you should not drink a lot of alcohol on a regular basis. Alcohol can increase the chance of getting lactic acidosis.
What are the side effects of GLUCOPHAGE and GLUCOPHAGE XR?
Call your doctor right away if you have any of the following symptoms, which could be signs of lactic acidosis:
Most people who have had lactic acidosis with metformin have other things that, combined with the metformin, led to the lactic acidosis. Tell your doctor if you have any of the following, because you have a higher chance for getting lactic acidosis with GLUCOPHAGE or GLUCOPHAGE XR if you:
Common side effects of GLUCOPHAGE and GLUCOPHAGE XR include diarrhea, nausea, and upset stomach. These side effects generally go away after you take the medicine for a while. Taking your medicine with meals can help reduce these side effects. Tell your doctor if the side effects bother you a lot, last for more than a few weeks, come back after they’ve gone away, or start later in therapy. You may need a lower dose or need to stop taking the medicine for a short period or for good.
About 3 out of every 100 people who take GLUCOPHAGE or GLUCOPHAGE XR have an unpleasant metallic taste when they start taking the medicine. It lasts for a short time.
GLUCOPHAGE and GLUCOPHAGE XR rarely cause hypoglycemia (low blood sugar) by themselves. However, hypoglycemia can happen if you do not eat enough, if you drink alcohol, or if you take other medicines to lower blood sugar.
How should I store GLUCOPHAGE and GLUCOPHAGE XR?
Store GLUCOPHAGE and GLUCOPHAGE XR at 68°F to 77°F (20°C to 25°C).
Keep GLUCOPHAGE and GLUCOPHAGE XR and all medicines out of the reach of children.
General information about the use of GLUCOPHAGE and GLUCOPHAGE XR
If you have questions or problems, talk with your doctor or other healthcare provider. You can ask your doctor or pharmacist for the information about GLUCOPHAGE and GLUCOPHAGE XR that is written for healthcare professionals. Medicines are sometimes prescribed for purposes other than those listed in a patient information leaflet. Do not use GLUCOPHAGE or GLUCOPHAGE XR for a condition for which it was not prescribed. Do not share your medicine with other people.
What are the ingredients of GLUCOPHAGE and GLUCOPHAGE XR?
Active ingredients of GLUCOPHAGE: metformin hydrochloride.
Inactive ingredients in each tablet of GLUCOPHAGE: povidone and magnesium stearate. In addition, the coating for the 500 mg and 850 mg tablets contain hypromellose and the coating for the 1000 mg tablet contains hypromellose and polyethylene glycol.
Active ingredients of GLUCOPHAGE XR: metformin hydrochloride.
Inactive ingredients in each tablet of GLUCOPHAGE XR 500 mg: sodium carboxymethyl cellulose, hypromellose, microcrystalline cellulose, and magnesium stearate.
Inactive ingredients in each tablet of GLUCOPHAGE XR 750 mg: sodium carboxymethyl cellulose, hypromellose, and magnesium stearate.
What is type 2 diabetes?
Type 2 diabetes is a condition in which your body does not make enough insulin, and the insulin that your body produces does not work as well as it should. Your body can also make too much sugar. When this happens, sugar (glucose) builds up in the blood. This can lead to serious medical problems.
The main goal of treating diabetes is to lower your blood sugar to a normal level.
High blood sugar can be lowered by diet and exercise, and by certain medicines when necessary.
Talk to your healthcare provider about how to prevent, recognize, and take care of low blood sugar (hypoglycemia), high blood sugar (hyperglycemia), and problems you have because of your diabetes.
