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Metformin ER 1000mg Modified Tabs

Manufacturer GLENMARK Active Ingredient Metformin Extended-Release Tablets(met FOR min) Pronunciation met-FOR-min
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).
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Drug Class
Antidiabetic agent
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Pharmacologic Class
Biguanide
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Pregnancy Category
Category B
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FDA Approved
Oct 2000
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DEA Schedule
Not Controlled

Overview

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What is this medicine?

Metformin ER is a medication used to help control high blood sugar levels in people with type 2 diabetes. It works by reducing the amount of sugar your liver makes, improving how your body uses insulin, and slowing down sugar absorption from your food. Because it's extended-release, you usually take it once a day, and it releases the medicine slowly over time.
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How to Use This Medicine

Taking Your Medication Correctly

To get the most benefit from your medication, it's essential to take it exactly as directed by your doctor. Carefully read all the information provided with your prescription, and follow the instructions closely.

Take your medication with meals to help your body absorb it properly.
 Continue taking your medication as prescribed by your doctor or healthcare provider, even if you start feeling well. This will help ensure that you receive the full benefits of the treatment.
If you're taking your medication once daily, take it with your evening meal.
 Swallow the medication whole, without chewing, breaking, or crushing it. If you have difficulty 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, away from direct light.
 Keep it in a dry place, avoiding humid environments like 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 regular 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.
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Lifestyle & Tips

  • Follow a healthy diet plan as recommended by your doctor or dietitian.
  • Engage in regular physical activity (e.g., 30 minutes of moderate exercise most days of the week).
  • Monitor your blood sugar levels regularly as instructed.
  • Avoid excessive alcohol intake, as it can increase the risk of a serious side effect called lactic acidosis.
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Available Forms & Alternatives

Available Strengths:

Dosing & Administration

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Adult Dosing

Standard Dose: Initial: 500 mg once daily with evening meal. Titrate by 500 mg weekly to a maximum of 2000 mg once daily or 1000 mg twice daily.
Dose Range: 500 - 2000 mg

Condition-Specific Dosing:

Type 2 Diabetes Mellitus: Initial: 500 mg once daily with evening meal. Increase by 500 mg weekly as tolerated, up to a maximum of 2000 mg once daily or 1000 mg twice daily. If switching from immediate-release, start with the same total daily dose of ER.
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Pediatric Dosing

Neonatal: Not established
Infant: Not established
Child: Not established for extended-release formulation. Immediate-release metformin is approved for children ≥10 years.
Adolescent: Not established for extended-release formulation. Immediate-release metformin is approved for adolescents ≥10 years.
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Dose Adjustments

Renal Impairment:

Mild: eGFR 60-89 mL/min/1.73m²: No dose adjustment needed. Monitor renal function at least annually.
Moderate: eGFR 45-59 mL/min/1.73m²: Assess benefits/risks. If continued, maximum dose is 1000 mg/day. Monitor renal function every 3-6 months. eGFR 30-44 mL/min/1.73m²: Not recommended to initiate. If already on metformin, discontinue.
Severe: eGFR <30 mL/min/1.73m²: Contraindicated.
Dialysis: Contraindicated.

Hepatic Impairment:

Mild: Use with caution. Monitor liver function.
Moderate: Use with caution. Increased risk of lactic acidosis.
Severe: Contraindicated due to increased risk of lactic acidosis.

Pharmacology

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Mechanism of Action

Metformin is a biguanide that improves glucose tolerance in patients with type 2 diabetes by lowering both basal and postprandial plasma glucose. Its primary mechanism of action is to decrease hepatic glucose production by inhibiting gluconeogenesis and glycogenolysis. It also increases insulin sensitivity in peripheral tissues (muscle and adipose) by increasing glucose uptake and utilization, and delays intestinal glucose absorption. Metformin does not stimulate insulin secretion and, therefore, does not cause hypoglycemia when used alone.
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Pharmacokinetics

Absorption:

Bioavailability: Approximately 50-60% (for immediate-release, ER is slower and more prolonged)
Tmax: 4-8 hours (for extended-release)
FoodEffect: Food prolongs Tmax and decreases Cmax for extended-release formulations, but overall absorption is not significantly affected. Taking with food can reduce gastrointestinal side effects.

Distribution:

Vd: 654 ± 358 L
ProteinBinding: <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)
Unchanged: >90%
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Pharmacodynamics

OnsetOfAction: Days to weeks for full therapeutic effect
PeakEffect: Weeks (for HbA1c reduction)
DurationOfAction: 24 hours (for extended-release)

Safety & Warnings

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BLACK BOX WARNING

Postmarketing cases of metformin-associated lactic acidosis have resulted in death, hypothermia, hypotension, and resistant bradyarrhythmias. The onset of metformin-associated lactic acidosis 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 were generally >5 mcg/mL. If metformin-associated lactic acidosis is suspected, discontinue metformin and institute general supportive measures promptly 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, having a radiological study with contrast, surgery and other procedures, hypoxic states (e.g., acute congestive heart failure), excessive alcohol intake, and hepatic impairment.
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Side Effects

Urgent Side Effects: Seek Medical Help Right Away

While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical attention immediately:

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 managing the condition, 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. Although 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 persist or bother you:

 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.
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Seek Immediate Medical Attention If You Experience:

  • Symptoms of lactic acidosis: unusual muscle pain, trouble breathing, unusual sleepiness, stomach pain, nausea, vomiting, feeling cold, dizziness, or a slow or irregular heartbeat. Seek immediate medical attention.
  • Symptoms of vitamin B12 deficiency: unusual tiredness, weakness, numbness or tingling in hands or feet, sore tongue, memory problems.
  • Severe diarrhea or vomiting, which can lead to dehydration and kidney problems.
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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.
 Certain health conditions, including:
+ Acidic blood problems
+ Kidney disease
+ Liver disease
If you have recently had a heart attack or stroke
 If you are experiencing any difficulties with eating or drinking, such as before undergoing a procedure or surgery

Additionally, if you are scheduled to have an exam or test that involves contrast media, or if you have had one within the past 48 hours, discuss this with your doctor.

To ensure your safety, it is crucial to provide your doctor and pharmacist with a comprehensive list of:

All prescription and over-the-counter medications you are taking
 Any natural products or vitamins you are using
* Your complete medical history, including any health problems

This information will help your doctor determine whether it is safe for you to take this medication with your other medications and health conditions. Never start, stop, or change the dose of any medication without first consulting your doctor.
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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, have your blood work checked as directed by your doctor and discuss the results with them.

Be aware that stress, such as fever, infection, injury, or surgery, can affect your blood sugar control. Changes in physical activity, exercise, or diet can also impact your blood sugar levels. Adhere to the diet and exercise plan recommended 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. In hot weather or during physical activity, be cautious 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 with your doctor. You may notice the appearance of the tablet in your stool, but this is a normal occurrence and not a cause for concern. If you have any questions or concerns, discuss them with 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 return of fertility 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.
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Overdose Information

Overdose Symptoms:

  • Lactic acidosis (most serious and common symptom)
  • Hypoglycemia (rare when used alone, but possible with very large overdose or in combination with other antidiabetic agents)
  • Severe gastrointestinal upset (nausea, vomiting, diarrhea)

What to Do:

Immediately contact emergency services or poison control (Call 1-800-222-1222 in the US). Treatment for metformin overdose, especially lactic acidosis, involves supportive measures and prompt hemodialysis to remove metformin and correct acidosis.

Drug Interactions

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Contraindicated Interactions

  • Iodinated contrast agents (temporarily discontinue before/at time of procedure and for 48 hours after)
  • Alcohol (excessive acute or chronic use)
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Major Interactions

  • Carbonic anhydrase inhibitors (e.g., topiramate, zonisamide, acetazolamide, dichlorphenamide) - increased risk of lactic acidosis
  • Drugs that reduce metformin clearance (e.g., cimetidine, ranolazine, dolutegravir, isavuconazole, trimethoprim, vandetanib) - increased metformin levels and risk of lactic acidosis
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Moderate Interactions

  • Diuretics (thiazide and loop) - may increase blood glucose, requiring dose adjustment of metformin
  • Corticosteroids - may increase blood glucose, requiring dose adjustment of metformin
  • Sympathomimetics - may increase blood glucose
  • Phenothiazines - may increase blood glucose
  • Thyroid products - may increase blood glucose
  • Oral contraceptives - may increase blood glucose
  • Niacin - may increase blood glucose
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Minor Interactions

  • Not typically categorized as minor for metformin, as most interactions are significant due to lactic acidosis risk or glycemic control.

Monitoring

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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.

Vitamin B12 levels

Rationale: Metformin can decrease vitamin B12 levels.

Timing: Consider baseline, especially in patients at risk for deficiency.

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Routine Monitoring

Renal function (eGFR)

Frequency: At least annually; more frequently (every 3-6 months) in patients with eGFR 45-59 mL/min/1.73m² or elderly patients.

Target: >60 mL/min/1.73m² (for full dose)

Action Threshold: Discontinue if eGFR falls below 30 mL/min/1.73m²; reassess if eGFR falls below 45 mL/min/1.73m².

HbA1c

Frequency: Every 3-6 months.

Target: Individualized, typically <7% for most adults.

Action Threshold: If target not met, consider dose adjustment or addition of other antidiabetic agents.

Blood Glucose (fasting and postprandial)

Frequency: Daily or as advised by healthcare provider.

Target: Individualized (e.g., FBG 80-130 mg/dL, PPG <180 mg/dL)

Action Threshold: Persistent high readings indicate need for dose adjustment or therapy change.

Vitamin B12 levels

Frequency: Periodically, especially if anemia or neuropathy symptoms develop.

Target: Normal range

Action Threshold: Supplement if levels are low.

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Symptom Monitoring

  • Symptoms of lactic acidosis (malaise, myalgia, respiratory distress, somnolence, abdominal distress, hypothermia, hypotension, bradyarrhythmias)
  • Gastrointestinal side effects (nausea, vomiting, diarrhea, abdominal discomfort)
  • Symptoms of vitamin B12 deficiency (fatigue, weakness, numbness, tingling, memory problems)

Special Patient Groups

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Pregnancy

Metformin is generally considered a first-line oral agent for gestational diabetes and may be continued in type 2 diabetes during pregnancy if benefits outweigh risks. It is Pregnancy Category B. Insulin is often preferred for glycemic control during pregnancy.

Trimester-Specific Risks:

First Trimester: Limited data, but generally considered low risk. Some studies suggest potential for lower birth weight, but overall safety profile is favorable compared to uncontrolled diabetes.
Second Trimester: Often continued for glycemic control. No specific increased risks identified.
Third Trimester: Often continued. May be associated with lower birth weight compared to insulin, but clinical significance is debated.
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Lactation

Metformin is considered compatible with breastfeeding (L1). It is excreted into breast milk in small amounts, but infant exposure is low and adverse effects are not expected.

Infant Risk: Low risk. Monitor breastfed infants for signs of hypoglycemia or gastrointestinal upset, though these are rare.
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Pediatric Use

Metformin extended-release is not approved for pediatric patients. Immediate-release metformin is approved for children 10 years and older for type 2 diabetes. Use in children requires careful consideration of renal function and potential for lactic acidosis.

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Geriatric Use

Use with caution in elderly patients due to increased likelihood of decreased renal function. Renal function should be assessed more frequently. Patients ≥65 years are at increased risk for lactic acidosis.

Clinical Information

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Clinical Pearls

  • Always take metformin ER with food (preferably the evening meal) to minimize gastrointestinal side effects and optimize absorption.
  • Educate patients thoroughly on the symptoms of lactic acidosis and when to seek immediate medical attention.
  • Remind patients to temporarily discontinue metformin before and for 48 hours after any radiological procedure involving iodinated contrast agents, and to restart only after renal function has been re-evaluated and found to be normal.
  • Monitor vitamin B12 levels periodically, especially in patients on long-term therapy or those with symptoms of deficiency.
  • Metformin does not cause hypoglycemia when used as monotherapy, but the risk increases when combined with insulin or insulin secretagogues (e.g., sulfonylureas).
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Alternative Therapies

  • Sulfonylureas (e.g., glipizide, glyburide, glimepiride)
  • DPP-4 inhibitors (e.g., sitagliptin, saxagliptin)
  • SGLT2 inhibitors (e.g., empagliflozin, canagliflozin, dapagliflozin)
  • GLP-1 receptor agonists (e.g., liraglutide, semaglutide, dulaglutide)
  • Thiazolidinediones (e.g., pioglitazone, rosiglitazone)
  • Insulin therapy
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Cost & Coverage

Average Cost: $15 - $60 per 30 tablets (1000mg ER)
Generic Available: Yes
Insurance Coverage: Tier 1 (Preferred Generic) or Tier 2 (Non-Preferred Generic)
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General Drug Facts

If your symptoms or health issues persist or worsen, it is essential to contact your doctor promptly. To ensure safe and effective treatment, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so it's a good idea 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, the amount, and the time it happened.