Glumetza 1000mg Tablets
WARNING: Rarely, metformin may cause too much lactic acid in the blood (lactic acidosis). The risk is higher in people who have kidney problems, liver problems, heart failure, use alcohol, or take certain other drugs, including topiramate. The risk is also higher in people who are 65 or older and in people who are having surgery, an exam or test with contrast, or other procedures. If lactic acidosis happens, it can lead to other health problems and can be deadly. Kidney tests may be done while taking this drug.Do not take this drug if you have a very bad infection, low oxygen, or a lot of fluid loss (dehydration).Call your doctor right away if you have signs of too much lactic acid in the blood (lactic acidosis) like confusion; fast breathing; fast or slow heartbeat; a heartbeat that does not feel normal; very bad stomach pain, upset stomach, or throwing up; feeling very sleepy; shortness of breath; feeling very tired or weak; very bad dizziness; feeling cold; or muscle pain or cramps. @ COMMON USES: It is used to lower blood sugar in patients with high blood sugar (diabetes).
Drug Class
Antidiabetic
Pharmacologic Class
Biguanide
Pregnancy Category
Not available
FDA Approved
Jun 2005
DEA Schedule
Not Controlled
Overview
What is this medicine?
Glumetza is a medicine used to help control high blood sugar in people with type 2 diabetes. It works by helping your body use insulin better, reducing the amount of sugar your liver makes, and decreasing the sugar your body absorbs from food. It's an extended-release tablet, meaning it releases the medicine slowly over time.
How to Use This Medicine
Taking Your Medication
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided to you and follow the instructions closely. Take your medication with meals to help your body absorb it properly. Even if you start to feel well, continue taking your medication as directed by your doctor or healthcare provider.
If you are taking your medication once daily, take it with your evening meal. Swallow the tablet whole - do not chew, break, or crush it. If you have trouble swallowing, consult with your doctor for guidance.
Storing and Disposing of Your Medication
To maintain the effectiveness and safety of your medication, store it at room temperature, protected from light. Keep it in a dry place, away from bathrooms. Ensure that all medications are kept in a secure location, out of the reach of children and pets.
What to Do If You Miss a Dose
If you miss a dose, skip it and resume your normal dosing schedule unless your doctor advises you to do otherwise. Do not take two doses at the same time or take extra doses to make up for the missed one.
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided to you and follow the instructions closely. Take your medication with meals to help your body absorb it properly. Even if you start to feel well, continue taking your medication as directed by your doctor or healthcare provider.
If you are taking your medication once daily, take it with your evening meal. Swallow the tablet whole - do not chew, break, or crush it. If you have trouble swallowing, consult with your doctor for guidance.
Storing and Disposing of Your Medication
To maintain the effectiveness and safety of your medication, store it at room temperature, protected from light. Keep it in a dry place, away from bathrooms. Ensure that all medications are kept in a secure location, out of the reach of children and pets.
What to Do If You Miss a Dose
If you miss a dose, skip it and resume your normal dosing schedule unless your doctor advises you to do otherwise. Do not take two doses at the same time or take extra doses to make up for the missed one.
Lifestyle & Tips
- Take Glumetza with your evening meal to help reduce stomach upset and improve absorption.
- Swallow the tablet whole; do not crush, chew, or break it, as this will affect its extended-release properties.
- Follow a healthy diet plan recommended by your doctor or dietitian.
- Engage in regular physical activity as advised by your healthcare provider.
- Limit alcohol intake, as excessive alcohol can increase the risk of a serious side effect called lactic acidosis.
- Stay well-hydrated, especially during illness or strenuous exercise.
Available Forms & Alternatives
Available Strengths:
Generic Alternatives:
Dosing & Administration
Adult Dosing
Standard Dose:
Initial: 500 mg extended-release orally once daily with the evening meal. Titration: Increase by 500 mg weekly up to a maximum of 2000 mg once daily with the evening meal. Glumetza 1000mg is a higher strength for maintenance.
Dose Range:
500 - 2000 mg
Condition-Specific Dosing:
Type 2 Diabetes Mellitus:
Initial: 500 mg extended-release orally once daily with the evening meal. Titrate in 500 mg increments weekly up to a maximum of 2000 mg once daily with the evening meal. If glycemic control is not achieved with 2000 mg once daily, consider 1000 mg twice daily.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established for Glumetza (ER formulation). Metformin IR is approved for children ≥10 years.
Adolescent:
Not established for Glumetza (ER formulation). Metformin IR is approved for adolescents ≥10 years.
Dose Adjustments
Renal Impairment:
Mild:
eGFR 60-89 mL/min/1.73m²: No dose adjustment needed. Monitor eGFR annually.
Moderate:
eGFR 45-59 mL/min/1.73m²: Not recommended to initiate. If already on metformin, assess benefits/risks of continuing; if continued, reduce dose by 50% and monitor eGFR every 3-6 months. eGFR 30-44 mL/min/1.73m²: Contraindicated to initiate. If already on metformin, discontinue.
Severe:
eGFR <30 mL/min/1.73m²: Contraindicated.
Dialysis:
Contraindicated in patients with end-stage renal disease or on dialysis due to increased risk of lactic acidosis.
Hepatic Impairment:
Mild:
No specific dose adjustment guidance; use with caution.
Moderate:
Contraindicated in patients with severe hepatic impairment due to increased risk of lactic acidosis.
Severe:
Contraindicated in patients with severe hepatic impairment due to increased risk of lactic acidosis.
Pharmacology
Mechanism of Action
Metformin is a biguanide that improves glycemic control by decreasing hepatic glucose production, decreasing intestinal absorption of glucose, and improving insulin sensitivity by increasing peripheral glucose uptake and utilization. It does not stimulate insulin secretion and therefore does not cause hypoglycemia in monotherapy.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 50-60% (oral, absolute)
Tmax:
4-8 hours (Glumetza ER)
FoodEffect:
Food increases the extent of absorption (AUC) and Tmax for Glumetza ER. It should be taken with the evening meal.
Distribution:
Vd:
654 ± 358 L (apparent volume of distribution after a single oral dose)
ProteinBinding:
Negligible (<5%)
CnssPenetration:
Limited
Elimination:
HalfLife:
Approximately 6.2 hours (plasma); 17.6 hours (blood)
Clearance:
Renal clearance is approximately 3.5 times greater than creatinine clearance, indicating tubular secretion.
ExcretionRoute:
Renal (primarily unchanged in urine)
Unchanged:
>90%
Pharmacodynamics
OnsetOfAction:
Gradual, typically within days to weeks for full glycemic effect.
PeakEffect:
Peak glucose-lowering effect typically seen after several weeks of consistent dosing.
DurationOfAction:
Approximately 24 hours for extended-release formulations.
Safety & Warnings
BLACK BOX WARNING
Postmarketing cases of metformin-associated lactic acidosis have resulted in death, hypothermia, hypotension, and resistant bradyarrhythmias. The onset is often subtle, accompanied only by nonspecific symptoms such as malaise, myalgias, respiratory distress, somnolence, and abdominal distress. Metformin-associated lactic acidosis was characterized by elevated blood lactate levels (>5 mmol/L), anion gap acidosis (without evidence of ketonuria or ketonemia), and an increased lactate/pyruvate ratio; metformin plasma levels generally >5 mcg/mL. If acidosis is suspected, discontinue Glumetza and institute general supportive measures in a hospital setting. Prompt hemodialysis is recommended. Risk factors include renal impairment, concomitant use of certain drugs (e.g., carbonic anhydrase inhibitors), age 65 years or greater, radiological studies with contrast, surgery and other procedures, hypoxic states (e.g., acute congestive heart failure), excessive alcohol intake, and hepatic impairment.
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Stomach problems that occur later during treatment, which may be a sign of lactic acidosis (an acid health problem in the blood)
Low blood sugar, which can be characterized by:
+ Dizziness
+ Headache
+ Feeling sleepy or weak
+ Shaking
+ Fast heartbeat
+ Confusion
+ Hunger
+ Sweating
If you experience low blood sugar, follow your doctor's instructions for treatment, which may include taking glucose tablets, liquid glucose, or some fruit juices.
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. Contact your doctor or seek medical help if you experience any of the following side effects or if they bother you or do not go away:
Stomach pain or heartburn
Gas
Diarrhea
Upset stomach or vomiting
Feeling tired or weak
* Headache
This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Stomach problems that occur later during treatment, which may be a sign of lactic acidosis (an acid health problem in the blood)
Low blood sugar, which can be characterized by:
+ Dizziness
+ Headache
+ Feeling sleepy or weak
+ Shaking
+ Fast heartbeat
+ Confusion
+ Hunger
+ Sweating
If you experience low blood sugar, follow your doctor's instructions for treatment, which may include taking glucose tablets, liquid glucose, or some fruit juices.
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. Contact your doctor or seek medical help if you experience any of the following side effects or if they bother you or do not go away:
Stomach pain or heartburn
Gas
Diarrhea
Upset stomach or vomiting
Feeling tired or weak
* Headache
This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Symptoms of lactic acidosis: unusual muscle pain, trouble breathing, stomach pain, feeling cold, dizziness or lightheadedness, slow or irregular heartbeat, unusual tiredness or weakness.
- Symptoms of low blood sugar (hypoglycemia) if taken with other diabetes medications: sweating, shaking, fast heartbeat, hunger, blurred vision, dizziness, tingling hands/feet.
- Symptoms of vitamin B12 deficiency: unusual tiredness, weakness, numbness or tingling in hands or feet, sore tongue, memory problems.
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
Certain health conditions, including:
+ Acidic blood problems
+ Kidney disease
+ Liver disease
Recent medical events, such as a heart attack or stroke
Any difficulties with eating or drinking, including situations where you may be required to fast before a procedure or surgery
* Upcoming or recent exams or tests that involve contrast agents, particularly if they have taken place within the past 48 hours
This list is not exhaustive, and it is crucial to discuss all your medications (prescription, over-the-counter, natural products, and vitamins) and health issues with your doctor and pharmacist. They will help determine if it is safe to take this medication in conjunction with your other treatments and health conditions. Never start, stop, or adjust the dosage of any medication without first consulting your doctor.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
Certain health conditions, including:
+ Acidic blood problems
+ Kidney disease
+ Liver disease
Recent medical events, such as a heart attack or stroke
Any difficulties with eating or drinking, including situations where you may be required to fast before a procedure or surgery
* Upcoming or recent exams or tests that involve contrast agents, particularly if they have taken place within the past 48 hours
This list is not exhaustive, and it is crucial to discuss all your medications (prescription, over-the-counter, natural products, and vitamins) and health issues with your doctor and pharmacist. They will help determine if it is safe to take this medication in conjunction with your other treatments and health conditions. Never start, stop, or adjust the dosage of any medication without first consulting your doctor.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. Before consuming alcohol, discuss the potential risks with your doctor.
If you experience low blood sugar, do not operate a vehicle, as this can increase your risk of being involved in an accident. Monitor your blood sugar levels as instructed by your doctor. Additionally, follow your doctor's recommendations for regular blood tests to ensure your health is not adversely affected.
During periods of stress, such as fever, infection, injury, or surgery, your blood sugar levels may be more challenging to control. Changes in physical activity, exercise, or diet can also impact your blood sugar levels. Adhere to the diet and exercise plan prescribed by your doctor to maintain optimal blood sugar control.
If you experience diarrhea or vomiting, contact your doctor promptly, as you may need to increase your fluid intake to prevent excessive fluid loss. Be cautious in hot weather or during intense physical activity, and drink plenty of fluids to avoid dehydration.
Long-term treatment with metformin may lead to a decrease in vitamin B-12 levels. If you have a history of low vitamin B-12 levels, consult your doctor to discuss potential implications. You may notice the appearance of the tablet in your stool; however, this is a normal occurrence and not a cause for concern. If you have any questions or concerns, consult your doctor.
If you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects. Women of childbearing age who have not been ovulating may experience a renewed risk of pregnancy while taking this medication. To avoid pregnancy, use birth control measures while taking this drug.
If you are pregnant, plan to become pregnant, or are breastfeeding, inform your doctor, as they will need to discuss the potential benefits and risks of this medication to you and your baby.
If you experience low blood sugar, do not operate a vehicle, as this can increase your risk of being involved in an accident. Monitor your blood sugar levels as instructed by your doctor. Additionally, follow your doctor's recommendations for regular blood tests to ensure your health is not adversely affected.
During periods of stress, such as fever, infection, injury, or surgery, your blood sugar levels may be more challenging to control. Changes in physical activity, exercise, or diet can also impact your blood sugar levels. Adhere to the diet and exercise plan prescribed by your doctor to maintain optimal blood sugar control.
If you experience diarrhea or vomiting, contact your doctor promptly, as you may need to increase your fluid intake to prevent excessive fluid loss. Be cautious in hot weather or during intense physical activity, and drink plenty of fluids to avoid dehydration.
Long-term treatment with metformin may lead to a decrease in vitamin B-12 levels. If you have a history of low vitamin B-12 levels, consult your doctor to discuss potential implications. You may notice the appearance of the tablet in your stool; however, this is a normal occurrence and not a cause for concern. If you have any questions or concerns, consult your doctor.
If you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects. Women of childbearing age who have not been ovulating may experience a renewed risk of pregnancy while taking this medication. To avoid pregnancy, use birth control measures while taking this drug.
If you are pregnant, plan to become pregnant, or are breastfeeding, inform your doctor, as they will need to discuss the potential benefits and risks of this medication to you and your baby.
Overdose Information
Overdose Symptoms:
- Lactic acidosis (severe metabolic acidosis with elevated lactate levels)
- Hypoglycemia (if taken with other antidiabetic agents or in very high doses)
What to Do:
Seek immediate medical attention or call Poison Control at 1-800-222-1222. Treatment for metformin overdose is primarily supportive and involves correcting lactic acidosis. Hemodialysis is highly effective in removing metformin and lactate from the blood.
Drug Interactions
Contraindicated Interactions
Major Interactions
- Carbonic anhydrase inhibitors (e.g., topiramate, zonisamide, acetazolamide, dichlorphenamide) - may increase risk of lactic acidosis
- Drugs that reduce metformin clearance (e.g., cimetidine, ranolazine, dolutegravir, isavuconazonium, trimethoprim, vandetanib) - may increase metformin levels and risk of lactic acidosis
Moderate Interactions
- Nifedipine (may increase metformin absorption and Cmax)
- Furosemide (may increase metformin plasma concentration)
- Cationic drugs (e.g., amiloride, digoxin, morphine, procainamide, quinidine, quinine, triamterene, trimethoprim, vancomycin) that are eliminated by renal tubular secretion - may compete with metformin for renal tubular transport
- Thiazide diuretics, corticosteroids, phenothiazines, thyroid products, estrogens, oral contraceptives, phenytoin, nicotinic acid, sympathomimetics, calcium channel blockers, isoniazid (may cause hyperglycemia, requiring dose adjustment of metformin)
Minor Interactions
- Not available
Monitoring
Baseline Monitoring
Renal function (eGFR)
Rationale: To assess kidney function and determine appropriate dosing or contraindication.
Timing: Prior to initiation of therapy.
HbA1c
Rationale: To establish baseline glycemic control.
Timing: Prior to initiation of therapy.
Fasting Plasma Glucose (FPG)
Rationale: To establish baseline glycemic control.
Timing: Prior to initiation of therapy.
Routine Monitoring
Renal function (eGFR)
Frequency: At least annually; more frequently (e.g., every 3-6 months) in patients at risk for renal impairment (e.g., elderly, those with moderate renal impairment).
Target: >60 mL/min/1.73m² (for full dose)
Action Threshold: Discontinue if eGFR falls below 30 mL/min/1.73m²; reassess if eGFR 30-44 mL/min/1.73m².
HbA1c
Frequency: Every 3-6 months
Target: Individualized, typically <7% for most adults
Action Threshold: Above target range indicates need for dose adjustment or additional therapy.
Fasting Plasma Glucose (FPG)
Frequency: Periodically, as needed for glycemic control assessment
Target: Individualized, typically 80-130 mg/dL
Action Threshold: Above target range indicates need for dose adjustment or additional therapy.
Vitamin B12 levels
Frequency: Periodically, especially in patients with risk factors for B12 deficiency (e.g., prolonged use, malabsorption, vegetarian diet)
Target: Normal range
Action Threshold: If low, consider supplementation or discontinuation of metformin.
Symptom Monitoring
- Symptoms of lactic acidosis (e.g., malaise, myalgia, respiratory distress, somnolence, abdominal distress, hypothermia, hypotension, resistant bradyarrhythmias)
- Symptoms of vitamin B12 deficiency (e.g., peripheral neuropathy, anemia, fatigue)
- Symptoms of hypoglycemia (if used in combination with insulin or sulfonylureas)
Special Patient Groups
Pregnancy
Metformin is generally considered a preferred oral agent for gestational diabetes and may be continued in type 2 diabetes during pregnancy if benefits outweigh risks. Consult with a healthcare provider.
Trimester-Specific Risks:
First Trimester:
Limited data, but generally considered low risk. No increased risk of congenital malformations observed.
Second Trimester:
Often continued for glycemic control.
Third Trimester:
Often continued for glycemic control.
Lactation
Metformin is excreted into breast milk in small amounts. It is generally considered compatible with breastfeeding due to low infant exposure and lack of reported adverse effects in breastfed infants.
Infant Risk:
Low risk. Monitor infant for signs of hypoglycemia or gastrointestinal upset, though these are rare.
Pediatric Use
Glumetza (metformin ER) is not approved for pediatric patients. Metformin immediate-release is approved for children 10 years and older with type 2 diabetes.
Geriatric Use
Use with caution due to increased likelihood of decreased renal function in elderly patients. Renal function should be assessed more frequently. The maximum recommended dose may be lower based on eGFR.
Clinical Information
Clinical Pearls
- Glumetza is an extended-release formulation; patients should be instructed not to crush, chew, or break the tablets.
- The tablet matrix may be visible in the stool, which is normal and does not indicate that the medication was not absorbed.
- Always discontinue metformin prior to or at the time of an iodinated contrast imaging procedure and for at least 48 hours afterward, or until renal function has been re-evaluated and found to be stable.
- Educate patients on the symptoms of lactic acidosis and the importance of seeking immediate medical attention if they occur.
- Consider periodic monitoring of vitamin B12 levels, especially with long-term use, as metformin can decrease B12 absorption.
Alternative Therapies
- Sulfonylureas (e.g., glipizide, glyburide, glimepiride)
- DPP-4 inhibitors (e.g., sitagliptin, saxagliptin)
- SGLT2 inhibitors (e.g., canagliflozin, dapagliflozin, empagliflozin)
- GLP-1 receptor agonists (e.g., liraglutide, semaglutide)
- Thiazolidinediones (e.g., pioglitazone, rosiglitazone)
- Insulin
- Alpha-glucosidase inhibitors (e.g., acarbose, miglitol)
Cost & Coverage
Average Cost:
Varies widely, typically $100-$300+ per 30 tablets (Glumetza 1000mg)
Generic Available:
Yes
Insurance Coverage:
Tier 2 or 3 (Brand Glumetza); Tier 1 (Generic Metformin ER)
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about your medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide details about the medication taken, including the amount and time of ingestion.