Understanding Metformin: What is the alternative name for metformin?

October 9, 2025 •

3 min read

Metformin is the most widely prescribed oral medication for type 2 diabetes worldwide. Many patients and caregivers wonder: what is the alternative name for metformin, and what other information is crucial to know about this common drug?

Quick Summary

Alternative names for metformin are its various brand names, most famously Glucophage, along with others like Glumetza, Fortamet, and Riomet. It is a biguanide medication used to treat Type 2 diabetes, often as a first-line therapy.

Key Points

Brand Names: The alternative names for generic metformin are its various brand names, such as Glucophage, Glumetza, Fortamet, and Riomet.
Generic vs. Brand: Metformin is the generic, active ingredient, while names like Glucophage are brand names for specific commercial products.
Drug Class: Metformin is the sole member of the biguanide class of oral diabetes medications available in many regions.
Mechanism: It lowers blood sugar by decreasing glucose production in the liver and improving the body's sensitivity to insulin.
Primary Use: It is widely recommended as the first-line medication for the treatment of Type 2 diabetes.
Formulations: Metformin comes in immediate-release (IR) and extended-release (ER) forms, which have different dosing frequencies.
Key Side Effect: A rare but life-threatening complication is lactic acidosis, which requires immediate medical attention.
Vitamin B12 Risk: Long-term use of metformin can be associated with a vitamin B12 deficiency.

The Generic vs. Brand Name Distinction

In pharmaceuticals, a drug typically has a generic name (the active chemical ingredient) and one or more brand names (given by the manufacturer). Metformin is the generic name, and it is sold under various brand names. It's important to note that different brand-name versions, especially extended-release formulations, may not be interchangeable.

Common Metformin Brand Names

The generic drug metformin is available under several brand names, though the availability of some may vary:

Glucophage: A well-known brand name for metformin. While the immediate-release brand-name version has been discontinued in the U.S., the generic is widely available.
Glucophage XR: The extended-release version of Glucophage.
Fortamet: An extended-release product; the brand name is no longer available, but the generic is.
Glumetza: Another extended-release product with a specific delivery system.
Riomet: A liquid formulation of metformin.

Metformin's Role as a Biguanide

Metformin belongs to the biguanide class of drugs and is currently the only drug in this class used for diabetes treatment in many regions. It works differently than medications that stimulate insulin production.

How Does Metformin Improve Blood Sugar Control?

Metformin lowers blood sugar through several mechanisms:

It primarily reduces the amount of glucose produced and released by the liver.
It increases the body's sensitivity to insulin.
It can decrease the absorption of glucose from the intestines.

Common Uses and Indications

Metformin is primarily used to treat Type 2 diabetes and is recommended as a first-line therapy by the American Diabetes Association (ADA), alongside lifestyle changes.

It is also used off-label for other conditions, including:

Polycystic Ovary Syndrome (PCOS): By improving insulin sensitivity, metformin can help regulate menstrual cycles and potentially improve fertility in women with PCOS.
Diabetes Prevention: It may be prescribed to individuals with prediabetes at high risk of developing Type 2 diabetes.
Antipsychotic-Induced Weight Gain: Metformin can help manage weight gain caused by certain antipsychotic medications.

Extended-Release (ER) and Immediate-Release (IR) Formulations

Metformin is available in immediate-release (IR) and extended-release (ER) forms. The choice depends on factors like tolerance and dosing needs. The formulations differ in how the medication is released and how often it needs to be taken.


Feature	Immediate-Release (IR) Metformin	Extended-Release (ER) Metformin
Dosing Frequency	Typically taken two to three times per day with meals.	Usually taken once daily, often with the evening meal.
Mechanism	Releases the medication into the body quickly after ingestion.	Releases the medication slowly over an extended period.
Side Effects	Often associated with more pronounced gastrointestinal side effects, such as diarrhea.	Designed to cause fewer gastrointestinal side effects due to slower absorption.

Potential Side Effects and Precautions

Metformin is generally safe, but like all medications, it has potential side effects.

Common Side Effects

Gastrointestinal Distress: Diarrhea, nausea, stomach upset, and gas are common, especially when starting treatment. Taking it with food can help.
Taste Changes: A metallic taste is occasionally reported.
Vitamin B12 Deficiency: Long-term use may reduce vitamin B12 levels; monitoring is recommended.

Serious Side Effect: Lactic Acidosis

A rare but serious risk is lactic acidosis, a build-up of lactic acid in the blood.

Risk factors include:

Severe Kidney Impairment: Impaired kidney function can lead to metformin accumulation.
Excessive Alcohol Intake: Alcohol increases the risk.
Heart or Liver Disease: Pre-existing conditions can increase risk.
Severe Infection or Surgery: Doctors may temporarily stop metformin during these times.

Conclusion

In summary, the alternative names for metformin are its various brand names, including well-known options like Glucophage, Glumetza, Fortamet, and Riomet. Metformin is a biguanide medication and a first-line treatment for Type 2 diabetes, working by reducing glucose production in the liver and improving insulin sensitivity. While it is generally safe, being aware of potential side effects, particularly the rare risk of lactic acidosis (especially with kidney issues), is crucial. Always follow your doctor's guidance and provide your complete medical history and list of medications for safe and effective use. For further information on diabetes management, the American Diabetes Association is a valuable resource.

Frequently Asked Questions

Glucophage is one of the most widely known brand names for metformin, although some brand versions have been discontinued. Various generics for both immediate-release and extended-release versions are available.

Yes, Glucophage is a brand name for the generic drug metformin. They contain the exact same active ingredient. When Glucophage was on the market, it was used to refer to the branded version of the medication.

The main difference is the rate of absorption and dosing frequency. Immediate-release (IR) metformin is typically taken two to three times daily, while extended-release (ER) versions are usually taken once daily. The ER version is often better tolerated by the stomach.

Metformin primarily works by reducing the amount of glucose produced by the liver. It also helps increase your body's sensitivity to the insulin it produces, making the insulin more effective at clearing glucose from the blood.

Common side effects include gastrointestinal issues such as diarrhea, nausea, stomach upset, and gas. These can often be reduced by taking the medication with food, especially when first starting treatment.

While not specifically a weight loss drug, some individuals taking metformin may experience a modest amount of weight loss. Unlike some other diabetes medications, it does not typically cause weight gain.

Metformin is generally not suitable for people with severe kidney or liver problems, certain types of metabolic acidosis, or those who consume excessive alcohol. Doctors should assess kidney function before prescribing.

When taken alone, metformin rarely causes dangerously low blood sugar levels. However, the risk of hypoglycemia increases significantly when it is combined with other diabetes medications that stimulate insulin production, such as sulfonylureas.

Excessive alcohol consumption while on metformin increases the risk of a serious side effect called lactic acidosis. It is important to discuss alcohol intake with a doctor.