- How Does It Work?
- Side Effects
- Drug Interactions
- Safety & Pregnancy
Brand Name: Fortamet, Glumetza, Glucophage, Riomet, Riomet ER
Generic Name: metformin
Drug Class: Antidiabetics, Biguanides
What is metformin? How does it work (mechanism of action)?
Metformin is an oral medication that lowers blood glucose (sugar) by influencing the body's sensitivity to insulin and is used for treating type 2 diabetes. Insulin is a hormone produced by the pancreas that controls glucose levels in the blood by reducing the amount of glucose made by the liver and by increasing the removal of glucose from the blood by muscle and fat tissues. As a result, insulin causes blood glucose levels to fall. Diabetes is caused by a decrease in the production of insulin that causes increased production of glucose by the liver, and reduced uptake (and effects) of insulin on fat and muscle tissues. Metformin acts by increasing the sensitivity of the liver, muscle, fat, and other tissues to the uptake and effects of insulin. These actions lower the level of sugar in the blood.
Unlike glucose-lowering drugs of the sulfonylurea class, for example, glyburide (Micronase, DiaBeta) or glipizide (Glucotrol), metformin does not increase the concentration of insulin in the blood and, therefore, does not cause excessively low blood glucose levels (hypoglycemia) when used alone. In scientific studies, metformin reduced the complications of diabetes such as heart disease, blindness, and kidney disease
Metformin is available under the following different brand names: Glucophage, Glucophage XR, Fortamet, Glumetza, and Riomet.
The FDA approved metformin in December 1994.
What are the side effects of metformin?
The most common side effects of metformin are
These symptoms occur in one out of every three patients. These side effects may be severe enough to cause therapy to be discontinued in one out of every 20 patients. These side effects are related to the dose of the medication and may decrease if the dose is reduced.
Metformin may also cause:
- weakness or lack of energy
- gas (flatulence)
- respiratory tract infections,
- low levels of vitamin B-12,
- low blood glucose (hyperglycemia)
- muscle pain,
- heartburn, and
A serious but rare side effect of metformin is lactic acidosis. Lactic acidosis occurs in one out of every 30,000 patients and is fatal in 50% of cases. The symptoms of lactic acidosis are
- trouble breathing,
- abnormal heartbeats,
- unusual muscle pain,
- stomach discomfort,
- light-headedness, and
- feeling cold.
Patients at risk for lactic acidosis include those with reduced function of the
What are the uses for metformin?
- Metformin is used for treating type 2 diabetes in adults and children. It may be used alone or in combination with other diabetic medications.
- Metformin also has been used to prevent the development of diabetes in people who are at risk.
- Treatment of polycystic ovaries
- Weight gain due to medications used for treating psychoses.
What is the dosage for metformin?
- For treating type 2 diabetes in adults, metformin (immediate release) usually is begun at a dose of 500 mg twice a day or 850 mg once daily. The dose is gradually increased by 500 mg weekly or 850 mg every two weeks as tolerated and based on the response of the levels of glucose in the blood. The maximum daily dose is 2550 mg given in three divided doses.
- If extended tablets are used, the starting dose is 500 mg or 1000 mg daily with the evening meal.
- The dose can be increased by 500 mg weekly up to a maximum dose of 2000 mg except for Fortamet (2500 mg of Fortamet, once daily or in two divided doses).
- Glumetza tablets (500 -1000mg formulations are given once daily (either 1000 to 2000mg).
- Fortamet and Glumetza are modified-release formulations of metformin. Metformin should be taken with meals.
- For pediatric patients 10-16 years of age, the starting dose is 500 mg twice a day.
- The dose can be increased by 500 mg weekly up to a maximum dose of 2000 mg in divided doses.
- Children older than 17 years of age may receive 500 mg of extended-release tablets daily up to a maximum dose of 2000 mg daily.
- Extended-release tablets are not approved for children younger than 17 years of age.
- Metformin-containing drugs may be safely used in patients with mild to moderate renal impairment. Renal function should be assessed before starting treatment and at least yearly.
- Metformin should not be used by patients with an estimated glomerular filtration rate (eGFR) below 30 mL/minute/1.73 m2 and starting metformin in patients with an eGFR between 30-45 mL/minute/1.73 m2 is not recommended.
- Metformin should be stopped at the time of or before administering iodinated contrast in patients with an eGFR between 30 and 60 mL/minute/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.
- Kidney function should be evaluated 48 hours after receiving contrast and metformin may be restarted if kidney function is stable.
Which drugs or supplements interact with metformin?
- Cimetidine (Tagamet), by decreasing the elimination of metformin from the body, can increase the amount of metformin in the blood by 40%. This may increase the frequency of side effects from metformin.
- Ioversol (Optiray) and other iodinated contrast media may reduce kidney function, which reduces the elimination of metformin, leading to increased concentrations of metformin in the blood. Metformin should be stopped 48 hours before and after the use of contrast media.
- Thiazide diuretics, steroids, estrogens, and oral contraceptives may increase blood glucose and reduce the effect of metformin. When these drugs are stopped, patients should be closely observed for signs of low blood glucose.
- Alcohol consumption increases the effect of metformin on lactate production, increasing the risk of lactic acidosis.
- Serious Interactions with Metformin include:
- Contrast media (iodinated)
Is metformin safe to take if I'm pregnant or breastfeeding?
What else should I know about metformin?
- Metformin is available as
- Tablets: 500, 850, and 1000 mg
- Tablets (extended release): 500, 750, and 1000 mg.
- Solution: 100 mg/ ml
- Metformin should be stored at room temperature between 20 C to 25 C (68 F to 77 F).
- Metformin is available in generic versions of immediate-release and extended-release formulations.
- You need a prescription from your doctor to obtain metformin.
- Brand names available for metformin in the US include:
- Glucophage XR
Metformin (Glucophage, Glucophage XR, Glumetza, Fortamet, Riomet) is a medication prescribed to treat type 2 diabetes and the prevention of type 2 diabetes in patients who are at risk for type 2 diabetes. Side effects of metformin include loss of appetite, bloating, heartburn, gas, nausea, and vomiting.
Drug interactions, dosage, and pregnancy and breastfeeding safety information should be reviewed prior to taking this medication.
Multimedia: Slideshows, Images & Quizzes
Type 2 Diabetes: Signs, Symptoms, Treatments
Learn about type 2 diabetes warning signs, symptoms, diagnosis, and treatment options. Find out why thirst, headaches, and...
Diabetes: What Raises and Lowers Your Blood Sugar Level?
Want to lower your blood sugar? Learn to better control your glucose levels by preventing blood sugar spikes and swings to avoid...
Exercise and Fitness: 10 Budget-Friendly Exercise Gadgets
There are plenty of cheap and free ways to exercise. Learn about inexpensive ways to get in shape with the use of jump ropes,...
Diabetes Nerve Pain: Improving Diabetic Peripheral Neuropathy
Learn how to cope with the symptoms of diabetic peripheral neuropathy through pain management exercises. Find relief for diabetic...
Exercises for Seniors: Tips for Core, Balance, Stretching
Exercise for seniors is important for healthy and successful aging. Learn about core strengthening, balance exercises, and...
Learn about fat-fighting foods such as grapefruit, hot peppers, vinegar, and more. Discover the benefits along with surprising...
Top 15 Immune System Boosters
Immune system boosters include foods, supplements, and lifestyle habits to help you fight off infections. A healthy immune system...
Diabetes: How Blood Sugar Levels Affect Your Body
High blood sugar can be a sign of diabetes or prediabetes. The drugs that treat it sometimes cause low blood sugar too. WebMD...
7 Ways Water Benefits the Body
Drinking water benefits digestion, metabolism, toxin elimination, and other functions. Water promotes weight loss and helps...
Sugar Addiction Facts: Cravings, Hidden Sugar, and More in Pictures
Learn about sugar addiction to see why we often crave sweets and binge on carbs. Learn how sugar affects the brain and get tips...
How Diabetes Can Affect Your Feet
Learn more about diabetes related foot problems. For people with diabetes, too much glucose in the blood can cause serious foot...
Food Cravings Slideshow: Chocolate, Carbs, Salt, Sugar
Learn which food cravings can wreck your diet. Whether your craving something creamy or crunchy, sweet or salty, food cravings...
Healthy Eating: Snacks With 100 Calories or Less
The tastiest 100-calorie snacks offer quick, satisfying solutions to hunger. From edamame to ice cream, our experts help you with...
10 Benefits of Walking Quiz
Take this 10 Benefits of Walking Quiz to learn about the many health benefit of walking for exercise!
Diabetes Diet: Healthy Meal Plans for Diabetes-Friendly Eating
Discover the best and worst meals for diabetes-savvy dining. See how to avoid carbs and control your blood sugar with healthier...
Pictures of the 7 Most Effective Exercises to Do at the Gym or Home (and Tips to Improve Form)
These seven exercises deliver fitness results at home or in the gym. Start your training to better physical health with the most...
Type 2 Diabetes: Test Your Medical IQ
What causes type 2 diabetes? Can it be prevented? Take this online quiz and challenge your knowledge of this common condition....
Diabetes Quiz: Test Your Medical IQ
Take the Diabetes Quiz and learn the causes, signs, symptoms, and types of this growing epidemic. What does diabetes have to do...
Exercise and Fitness Quiz: Test Your IQ
Take our Exercise and Fitness Quiz and learn to maximize your fitness level with simple exercises that do not require major...
Metabolic Syndrome Quiz: Test Your Medical IQ
Metabolic syndrome is serious and you should be concerned. Learn the causes, symptoms, treatments, and complications of metabolic...
Affordable, Healthy Indulgences to Help You Relax
Isn't it time you took care of yourself? Good food, relaxation, laughter -- we offer 15 great ideas for affordable, healthy...
Diabetes Travel: Tips for Better Diabetes Control
Diabetes shouldn't stop you from traveling! Learn tips for packing diabetic supplies, controlling blood sugar while changing time...
Popular Dieting Myths and Facts
Can't tell fact from fiction about weight loss and healthy eating? Discover the truth behind some of the most common diet and...
No-Gym Workout in Pictures: Equipment, Routines, and More
Learn about this no-gym, at home quick workout. It can get you into great shape at home and shows the best moves for flat abs and...
Diabetes Diet: 11 Low-Sugar Drink Ideas
Searching for low-sugar drink ideas? This pictures slideshow has eleven beverages ideal for people with diabetes and those...
Diabetes: 15 Famous Celebrities With Diabetes
See pictures of celebrities that have been diagnosed with type 1 or type 2 diabetes including Mary Tyler Moore, Salma Hayek, and...
Slideshow: Diabetes Management in 10 Minutes
Learn 10 simple ways to better manage your diabetes. See tips for controlling blood sugar, diet and exercise and other helpful...
Pictures of the 7 Riskiest Workout Moves, and How to Improve Them
Working out is supposed to make you healthier--but some exercises can leave your body at risk of pain or injury. Some exercises...
12 Reasons to Love the Mediterranean Diet
The Mediterranean diet is a delicious way to eat healthy. We show you how to get the most from this diet with foods like olive...
Healthy Living: 20 Common Health Myths Exposed
Can vitamin C cure colds? Read as we dispel the half-truths and common myths of health, from X-rays to eggs, from the...
17 Must-Try Fitness Workouts in Pictures
Learn the latest exercise crazes such as TRX, pole dancing, Zumba, Kangoo jumps, boot camps, exergames and more that are designed...
Best and Worst-Appetizers: Spinach Dip, Potato Skins, and More
A tasty appetizer can be a great start to any meal--but some appetizers are diet disasters. Potato skins and cheese fries pack on...
Easy, Tasty Grilled Foods for Dinner Tonight in Pictures
Explore easy and tasty grilled foods. When your rushed to get dinner on the table, fire up the grill and use these delicious,...
10 Muscle-Building Exercises for Diabetes
Watch this slideshow on Diabetes and Exercise. If you have diabetes, see how strengthening your muscles with these 10 weight...
Benefits of Exercise: Fitness Facts Prove the Benefits of Working Out
The best way to lose weight? These fast facts show weight loss is possible for everyone trying to lose weight. From calories to...
The 30-Minute Fitness Routine
This quick, high-intensity 30-minute workout routine can make you look better and feel better. Discover the right way to do...
Healthy Fast Food Options: 10 Tips for a Weight Loss Diet
What healthy fast food options are around you? Most fast food can't compare to the health of a well-planned, balanced diet. But...
Exercise and Fitness: The 7-Minute Workout
The 7-minute workout provides a free, convenient way to get and stay fit. Discover these short, quick exercises that use your own...
Exercise Tips for Kids and the Whole Family
Exercise is great for kids, and fun activities for the whole family are there if you know how to find them. Learn how to lose...
Diet & Nutrition: The 10 Worst Foods in Your Fridge
What are the worst foods to eat in your fridge? From mayonnaise to ice cream and butter to processed lunch meats, learn about the...
Grocery Smarts: Right vs. Wrong Food Choices at the Supermarket
Grocery shopping means choosing the right foods and avoiding the wrong ones for a healthy diet. Low-fat snack ideas include...
Portion Control: Plate Photos to Lose Weight, Maintain Diet
Portion control can help with weight loss. The right plate amount can help you stick to a healthy diet. Learn to lose weight with...
Tips to Eat Healthy When You Dine Out in Pictures
Recognize the dangers of eating out and stay on your healthy diet at restaurants. Learn about healthy eating at restaurants,...
Related Disease Conditions
Diabetes (Type 1 and Type 2)
Diabetes is a chronic condition characterized by high levels of sugar (glucose) in the blood. The two types of diabetes are referred to as type 1 (insulin dependent) and type 2 (non-insulin dependent). Symptoms of diabetes include increased urine output, thirst, hunger, and fatigue. Treatment of diabetes depends on the type.
Type 2 Diabetes Diet Plan
A type 2 diabetes diet or a type 2 diabetic diet is important for blood sugar (glucose) control in people with diabetes to prevent complications of diabetes. There are a variety of type 2 diabetes diet eating plans such as the Mediterranean diet, Paleo diet, ADA Diabetes Diet, and vegetarian diets.Learn about low and high glycemic index foods, what foods to eat, and what foods to avoid if you have type 2 diabetes.
High Blood Sugar (Hyperglycemia)
Hyperglycemia or high blood sugar is a serious health problem for diabetics. There are two types of hyperglycemia, 1) fasting, and 2)postprandial or after meal hyperglycemia. Hyperglycemia can also lead to ketoacidosis or hyperglycemic hyperosmolar nonketotic syndrome (HHNS). There are a variety of causes of hyperglycemia in people with diabetes. Symptoms of high blood sugar may include increased thirst, headaches, blurred vision, and frequent urination.Treatment can be achieved through lifestyle changes or medications changes. Carefully monitoring blood glucose levels is key to prevention.
Low Blood Sugar (Hypoglycemia)
Low blood sugar or hypoglycemia occurs when blood sugar is dangerously low and is often complication of type 1 and type 2 diabetes. Learn about symptoms, dangers, and treatment.
Fatty Liver (NASH)
Nonalcoholic fatty liver disease or NASH occurs due to the accumulation of abnormal amounts of fat within the liver. Fatty liver most likely caused by obesity and diabetes. Symptoms of fatty liver disease are primarily the complications of cirrhosis of the liver; and may include mental changes, liver cancer, the accumulation of fluid in the body (ascites, edema), and gastrointestinal bleeding. Treatment for fatty liver includes avoiding certain foods and alcohol. Exercise, weight loss, bariatric surgery, and liver transplantation are treatments for fatty liver disease.
Type 2 Diabetes
Type 2 diabetes is a chronic condition that may be reversible with diet and lifestyle changes. Symptoms include excessive thirst, frequent urination, weight loss, fatigue, and an unusual odor to your urine. Most people don't know they have type 2 diabetes until they have a routine blood test. Treatment options include medications, a type 2 diabetes diet, and other lifestyle changes.
Insulin resistance is the diminished ability of cells to respond to the action of insulin in transporting glucose (sugar) from the bloodstream into muscle and other tissues. There are no signs or symptoms of insulin resistance. Causes of insulin can include conditions such as stress, obesity, metabolic syndrome, and steroid use. Some of the risk factors for insulin resistance include fatty liver, heart disease, strokes, peripheral vascular disease, high cholesterol, and smoking. Treatment for insulin resistance are lifestyle changes and if necessary, medication.
Diabetes Treatment: Medication, Diet, and Insulin
The major goal in treating diabetes is controlling elevated blood sugar without causing abnormally low levels of blood sugar. Type 1 diabetes is treated with: insulin, exercise, and a diabetic diet. Type 2 diabetes is first treated with: weight reduction, a diabetic diet, and exercise. When these measures fail to control the elevated blood sugar, oral medications are used. If oral medications are still insufficient, insulin medications are considered.
Prediabetes is a situation where a person's blood sugar levels are higher than they should be, but aren't high enough to be diagnosed with type 2 diabetes. There are no signs or symptoms of prediabetes. Some of the risk factors for prediabetes are high blood pressure, high cholesterol, heart disease, smoking, family history, poor diet, and lack of activity. Diet changes along with other healthy lifestyle changes are important in treating prediabetes.
Type 1 vs. Type 2 Diabetes: Differences
Diabetes mellitus is a metabolic condition in which a person's blood sugar (glucose) levels are too high. Over 29.1 million children and adults in the US have diabetes. Of that, 8.1 million people have diabetes and don't even know it. Type 1 diabetes (insulin-dependent, juvenile) is caused by a problem with insulin production by the pancreas. Type 2 diabetes (non-insulin dependent) is caused by: Eating a lot of foods and drinking beverages with simple carbohydrates (pizza, white breads, pastas, cereals, pastries, etc.) and simple sugars (donuts, candy, etc.) Consuming too many products with artificial sweeteners (We found out that they are bad for us!) Lack of activity Exercise Stress Genetics While the signs and symptoms of both types of diabetes are the same, which include: Increased urination Increased hunger Increased thirst Unexplained weight loss. However, the treatments are different. Type 1 diabetes is insulin dependent, which means a person with this type of diabetes requires treatment with insulin. People with type 2 diabetes require medication, lifestyle changes like eating a healthy diet, and getting regular exercise.
A diabetic diet, or diabetes diet helps keep blood glucose levels in the target range for patients. Exercise and medication may also help stabilize blood glucose levels. Keeping track of when you take your diabetic medicine, keeping track of food choices, eating the proper amount of fruits, vegetables, carbohydrates, and fats will also help maintain proper blood glucose levels.
What Are Polycystic Ovarian Syndrome (PCOS) Symptoms?
Polycystic ovarian syndrome (PCOS), also known by the name Stein-Leventhal syndrome, is a hormonal problem that causes women to have a variety of symptoms including irregular or no menstrual periods, acne, obesity, and excess hair growth. Treatment of PCOS depends partially on the woman's stage of life and the symptoms of PCOS.
The main features of metabolic syndrome include insulin resistance, hypertension (high blood pressure), cholesterol abnormalities, and an increased risk for clotting. Patients are most often overweight or obese. Lifestyle modification such as the Mediterranean diet, exercise, and quitting smoking are the preferred treatment of metabolic syndrome.
How to Prevent Diabetes Naturally
Prediabetes is a condition in which a person has early symptoms of diabetes, but has not yet fully developed the condition. If prediabetes is not treated with lifestyle changes, the person could develop type 2 diabetes. Type 2 diabetes and prediabetes can be prevented with lifestyle changes, for example, eating a healthy diet, getting more exercise, reducing stress, quitting smoking, reducing or managing blood pressure and cholesterol, and managing any other health conditions or risk factors that you may have for developing type 2 diabetes.
Types of Diabetes Type 2 Medications
Type 2 diabetes oral medications are prescribed to treat type 2 diabetes in conjuction with lifestyle changes like diet and exercise. There are nine classes of drugs approved for the treatment of type 2 diabetes. Examples of type 2 oral diabetes medications include acarbose (Precose), chlorpropamide (Diabinese), glipizide (Glucotrol, Glucotrol XL), and metformin (Glucophage). Side effects, drug interactions, warnings and precautions, dosage, and breastfeeding and pregnancy safety information should be reviewed prior to taking any medication.
Tips for Managing Type 1 and 2 Diabetes at Home
Managing your diabetes is a full time commitment. The goal of diabetic therapy is to control blood glucose levels and prevent the complications of diabetes. Information about exercise, diet, and medication will help you manage your diabetes better. Blood glucose reagent strips, blood glucose meters, urine glucose tests, tests for urinary ketones, continuous glucose sensors, and Hemoglobin A1C testing information will enable you to mange your diabetes at home successfully.
Treatment & Diagnosis
- Diabetes FAQs
- Exercise and Fitness FAQs
- Metabolic Syndrome FAQs
- Type 2 Diabetes FAQs
- 10 Benefits of Walking FAQs
- Drugs: Buying Prescription Drugs Online Safely
- Drugs: The Most Common Medication Errors
- Medication Disposal
- Dangers of Mixing Medications
- How To Reduce Your Medication Costs
- Pharmacy Visit, How To Get The Most Out of Your Visit
- Indications for Drugs: Approved vs. Non-approved
- What Are the Side Effects of Glucophage in People with PCOS?
- Generic Drugs, Are They as Good as Brand-Names?
Medications & Supplements
- metformin solution - oral, Riomet
- metformin sustained-action tablet - oral, Fortamet, Glucophage XR, Glume
- metformin - oral, Glucophage
- Drugs: Questions to Ask Your Doctor or Pharmacist about Your Drugs
- Drug Interactions
- Side Effects of Glucophage (metformin)
- glipizide and metformin
- Glucovance (glyburide/metformin)
- canagliflozin (Invokana)
- metformin and sitagliptin (Janumet)
- Side Effects of Janumet (metformin and sitagliptin)
- Synjardy XR (empagliflozin and metformin extended-release)
- Avandamet (rosiglitazone/metformin)
- Synjardy (empagliflozin and metformin)
- Side Effects of Glucovance (glyburide/metformin)
Prevention & Wellness
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.