The active ingredient in Metformin ER is metformin hydrochloride. It is a biguanide that works by reducing how much sugar your liver makes and the amount absorbed in your gut. It helps treat high blood sugar levels (hyperglycemia).

Follow all directions given to you by your doctor and read all documents provided, including the full Prescribing Information, FDA-Approved Product Labeling, Instructions for Use, and Medication Guide before using Metformin ER. However, the following is a synopsis of the general guidelines for the use of Metformin ER:

• You should not crush, split, or chew this tablet. Make sure to swallow the tablet whole.
• To minimize side effects, take metformin with your evening meal.
• Due to the film-coated tablets, you may see tablet shells in your stool, which is normal.
• Be sure to stay hydrated while taking this medication. If you are dehydrated, this increases your risk of lactic acidosis.
• If you are taking other blood sugar-lowering medications (insulin, sulfonylureas), you may be at risk of low blood glucose (hypoglycemia). If you have symptoms of low blood sugar, such as feeling shaky, confused, and very hungry, check your blood glucose. If it is below 4mmol/L (70mg/dL), take 15 grams of sugar and check again in 15 minutes. If it is still low, take more sugar.
• Do not drink alcohol while taking this medication, as there is an additive dizziness and risk of fainting.

Some mild or common side effects of Metformin ER include:

• Acid reflux (heartburn).
• Stomach pain.
• Diarrhea.
• Weight loss.
• Upset stomach.

Some individuals may experience serious side effects while using Metformin ER. These side effects may require immediate medical attention. If you experience any of the following, contact your healthcare provider or seek emergency medical help:

• Severe allergic reaction presenting with swelling of the face, lips, tongue, or throat, hives, and trouble breathing.
• Symptoms of lactic acidosis include muscle pain, trouble breathing, fatigue, and severe stomach pain from the buildup of lactic acid.
• Symptoms of low blood sugar such as feeling shaky, confused, and very hungry.
• Low vitamin B12 levels with long-term use. This can lead to an increased risk of anemia.

These are not all of the possible side effects from the use of metformin. You should always seek medical advice from your healthcare provider for any questions or concerns about your medical condition or treatment. Read all patient information, medication guides, or drug information sheets that come with this medication. You can also report adverse effects to the Food and Drug Administration at www.fda.gov/medwatch or 1-800-FDA-1088.

Before starting Metformin ER, it is crucial to discuss any existing health conditions with your healthcare provider. You should be sure that your healthcare provider is aware of all your medical conditions, including:

Heart failure, previous heart attack, or stroke.

Kidney problems.

An upcoming surgery or imaging (including X-ray).

Vitamin B12 deficiency.

Severe kidney disease.

Acute or chronic metabolic acidosis, including diabetic ketoacidosis.

History of serious hypersensitivity reaction to any component of this medication or other medications containing metformin.

The effects of metformin begin after your first dose, but it may take a few months before you notice the full effects of this medication.

When Metformin ER is taken with other prescription drugs, over-the-counter medications, vitamins, and supplements, it may change how they work or increase the frequency or severity of side effects. Make sure that you tell your healthcare professional about anything that you are taking to avoid any negative drug interactions, including:

Medications such as furosemide and nifedipine may increase levels of metformin, causing more side effects.

Carbonic anhydrase inhibitors such as topiramate can increase the risk of lactic acidosis when used with metformin.

Metformin ER is available in the following dosage forms and strengths: 500 mg and 1000 mg tablets.

It should be stored at room temperature out of the reach of children or pets.

Metformin ER is manufactured by several manufacturers of generic drugs.

This is the generic version of metformin extended-release. It is available under the brand names Glumetza, Fortamet, and Glucophage XR.

Barring any serious side effects as listed above, or under the direction of a physician, you should not stop this medication suddenly.

Metformin crosses the placenta and can increase the risk of low birth weight and later childhood obesity. Metformin is not the treatment of choice in pregnancy.

Talk to your doctor if you are already pregnant or if you have any plans to become pregnant. They will know or recommend what is best for you.

While metformin does pass into breast milk, it is in relatively low concentrations and should not be harmful to an infant.

Talk to your doctor if you are already breastfeeding or if you have any plans to breastfeed. They will know or recommend what is best for you.