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Fortamet

Generic name: metformin

Brand names: Glumetza, Fortamet, Glucophage XR, Riomet ER

Last updated November 2, 2026 0 views
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What is Fortamet?

Fortamet is used along with diet and exercise to help control blood sugar in people with type 2 diabetes mellitus (not for type 1 diabetes).

Fortamet may also be used for reasons not mentioned in this medication guide.

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How should I take Fortamet?

Follow all instructions on your prescription label and read all medication guides or instruction sheets. Your doctor may change your dose from time to time. Use the medicine exactly as directed.

Your dose may change if you switch to a different brand, strength, or form of Fortamet. Avoid medication errors by using it exactly as directed on the label or as prescribed by your doctor.

Take Fortamet with a meal, unless your doctor advises you otherwise. Some forms of metformin are only taken once a day with the evening meal. Follow your doctor's instructions.

Swallow the tablet whole; do not crush, chew, or break it.

Measure liquid medicine with the measuring device provided (not a kitchen spoon).

Part of a tablet shell may show up in your stool, but this will not reduce the medicine's effectiveness.

Blood sugar can be affected by stress, illness, surgery, exercise, alcohol use, or skipping meals.

Low blood sugar (hypoglycemia) can make you feel very hungry, dizzy, irritable, or shaky. To quickly treat hypoglycemia, eat or drink hard candy, crackers, raisins, fruit juice, or non-diet soda. Your doctor may prescribe glucagon injection for severe hypoglycemia.

Tell your doctor if you have frequent signs of high blood sugar (hyperglycemia) such as increased thirst or urination. Ask your doctor before changing your medication dosage.

Your blood sugar will need to be checked regularly, and you may need other medical tests, including checking your kidney function.

You may be prescribed other medications to help with your condition. Keep taking these medicines for as long as your doctor has prescribed.

Your treatment may also include diet, exercise, weight control, medical tests, and special medical care.

Store at room temperature away from moisture, heat, and light.

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Warnings

You should not use Fortamet if you have severe kidney disease, metabolic acidosis, or diabetic ketoacidosis (call your doctor for treatment).

You may develop lactic acidosis, which is a dangerous build-up of lactic acid in your blood. Call your doctor or seek emergency medical help if you experience unusual muscle pain, trouble breathing, stomach pain, dizziness, feeling cold, or feeling very weak or tired.

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Before taking this medicine

You should not use Fortamet if you are allergic to it, or if you have:

  • severe kidney disease; or
  • metabolic acidosis or diabetic ketoacidosis (call your doctor for treatment).

Tell your doctor if you have or have ever had:

  • high ketone levels in your blood or urine;
  • low levels of vitamin B12;
  • heart problems such as heart attack, heart failure, or stroke;
  • if you also use insulin or other oral diabetes medications;
  • if you are dehydrated;
  • if you drink large amounts of alcohol; or
  • liver or kidney disease.

You may develop lactic acidosis, which is a dangerous build-up of lactic acid in your blood. This may be more likely if you have other medical conditions, a severe infection, chronic alcoholism, or if you are 65 or older. Ask your doctor about your risk.

If you need to have surgery or any type of x-ray or CT scan using a dye that is injected into your veins, you may need to temporarily stop taking Fortamet. Make sure that your healthcare provider knows ahead of time that you are using this medication.

It is not known if Fortamet will harm an unborn baby. Follow your doctor's instructions about using this medicine if you are pregnant or become pregnant. Controlling diabetes is very important during pregnancy.

This medicine may stimulate ovulation in a premenopausal woman and may increase the risk of unintended pregnancy. Talk to your doctor about your risk.

Ask a doctor if it is safe to breastfeed while using this medicine.

Fortamet should not be given to a child younger than 10 years old. Some forms of metformin are not approved for use by anyone younger than 18 years old.

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Fortamet side effects

Get emergency medical help if you have signs of an allergic reaction: hives, difficulty breathing, swelling of your face, lips, tongue, or throat.

Some people using Fortamet develop lactic acidosis, which can be fatal. Get emergency medical help if you have: unusual muscle pain, trouble breathing, stomach pain, vomiting, fast/slow or irregular heartbeats, dizziness, feeling cold, or feeling very weak or tired.

Fortamet may cause serious side effects. Call your doctor right away if you have:

  • severely low blood sugar--extreme weakness, confusion, tremors, sweating, fast heartbeats, trouble speaking, nausea, vomiting, rapid breathing, fainting, and seizure (convulsions).

Common side effects of Fortamet may include:

  • low blood sugar;
  • dizziness, weakness or lack of energy;
  • headache;
  • altered sense of taste;
  • stomach pain or upset, heartburn;
  • indigestion, bloating, gas, nausea, vomiting, constipation, diarrhea; or
  • cold symptoms such as stuffy nose, sneezing, sore throat.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

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What happens if I miss a dose?

Take the medicine as soon as possible, but skip the missed dose if it is nearly time for your next dose. Do not take two doses at the same time.

This section was rewritten for readability and reviewed for meaning.

What happens if I overdose?

Seek emergency medical help or call the Poison Help line at 1-800-222-1222.

Avoid drinking alcohol. It can lower blood sugar and may raise your risk of lactic acidosis.

This section was rewritten for readability and reviewed for meaning.

What other drugs will affect Fortamet?

Many medicines can raise your risk of lactic acidosis or impact your blood sugar levels, and they may also affect Fortamet. This includes both prescription and over-the-counter medicines, vitamins, and herbal products. Inform your doctor about all other medicines you are using. Not all possible interactions are included here.

This section was rewritten for readability and reviewed for meaning.

Common questions about Fortamet

How long does metformin take to work?
Metformin will usually start lowering your blood sugar (glucose) levels in the first week of treatment, but it may take 2 to 3 months to see its full effect. Metformin is a preferred initial oral treatment for people with type 2 diabetes, and is usually taken on a long-term basis. It may be combined with other blood glucose-lowering treatments, if needed. Continue reading
When is the best time to take metformin?
Metformin is usually taken with meals to help reduce stomach side effects like nausea and diarrhea. Immediate-release metformin is typically taken twice daily with breakfast and dinner, while extended-release metformin is usually taken once daily with the evening meal. Follow your prescribed dosing schedule and take metformin consistently. Continue reading
What is the safest diabetes medication?
Metformin is widely considered the safest first-line medication for type 2 diabetes. With decades of clinical use and extensive safety data, it remains the preferred initial treatment according to the American Diabetes Association (ADA). However, the safest medication for any individual depends on their specific health profile, age, kidney function, and treatment goals. Continue reading
Why does metformin cause diarrhea?
Metformin causes diarrhea by changing gut bacteria, affecting bile acid absorption, blocking water absorption in the intestines, and increasing gut-stimulating hormones. These combined effects make stools looser and more frequent. Continue reading
Can you take metformin without food?
Yes, you can take metformin without food and it will still lower your blood sugar. But taking it on an empty stomach makes stomach side effects like nausea, diarrhea, gas and cramps more likely. That's why metformin is usually taken with meals: regular (immediate-release) tablets with meals two or three times a day, and extended-release tablets once a day with your evening meal. Continue reading
Does metformin lower A1C, if so how much?
When metformin is used alone as a single agent, it lowers A1C by about 1 to 1.5 percentage points (1-1.5%) on average, at standard therapeutic doses. A1C is a measure of longer-term blood sugar control. In most patients, metformin is suggested as the initial treatment for type 2 diabetes, but its glucose-lowering effect may not be adequate for all patients if used alone. Continue reading
Does metformin cause weight loss?
Metformin is generally considered weight neutral or modestly weight reducing, with average losses around 1–3 kg (2–7 lb) over several months in people with type 2 diabetes or obesity. Many people lose little or no weight, and the effect varies widely between individuals. Continue reading
Can you take metformin and Ozempic together?
Yes, metformin and Ozempic (semaglutide) are often used together under a healthcare provider’s guidance to manage type 2 diabetes. They work through different mechanisms to lower blood sugar and may also help with weight management, but both have specific safety considerations such as Ozempic’s boxed thyroid warning and metformin’s kidney function requirements. Continue reading

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Before you take this medicine: the information on this page is general and may not cover your personal circumstances. Read the label supplied with your medicine and ask a pharmacist or doctor if you are unsure, especially if you are pregnant, breastfeeding, taking other medicines or managing a long-term condition.
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