Medically reviewed by Jessica Swirble, PharmD Last updated on April 21, 2025
Drug Information | Side Effects | Use & Dosage | Request an Online Prescription
Metformin ER is a prescription medication used to manage blood sugar levels in patients with type 2 diabetes. It may also be used to treat prediabetes and induce ovulation in women with polycystic ovary syndrome (PCOS). It reduces the amount of glucose (blood sugar) absorbed from food and the amount of glucose produced by the liver. It also increases insulin sensitivity.
Metformin ER is prescribed to manage blood sugar levels in patients with type 2 diabetes mellitus. Type 2 diabetes is a chronic metabolic disorder characterized by elevated blood glucose levels, also known as “blood sugar.”
Type 2 diabetes occurs when the pancreas doesn’t produce enough insulin or your body doesn’t use it properly. Excessive blood sugar levels cause cells in the pancreas to release more insulin. High levels of insulin production cause cells in the body to become resistant to it, meaning that the cells cannot take in enough sugar to keep blood sugar levels from rising.
Metformin ER belongs to a class of medications known as biguanides. Biguanides help regulate blood sugar levels and improve insulin sensitivity. When you ingest metformin ER, it enters your bloodstream and travels to your liver. Here, metformin ER reduces the liver's glucose production and reduces the intestinal absorption of glucose. Doing so effectively lowers the overall amount of sugar circulating in your blood.
Additionally, metformin ER enhances the body's response to insulin, making your cells more receptive to this hormone. In type 2 diabetes, the pancreas can produce insulin, but cells in the body do not use it properly. Metformin ER’s mechanism helps lower blood sugar levels and makes muscle and fat tissue more sensitive to insulin, allowing the tissue to absorb more insulin and use glucose for energy.
Metformin ER is available in the following forms:
The dosage and frequency of use depend on the condition being treated, its severity, and how you respond to the medication.
Follow your healthcare provider's instructions regarding dosage and schedule. Do not exceed the prescribed dose or frequency of use without consulting your provider.
Metformin ER is used to manage type 2 diabetes mellitus. The effects can be noticeable within a few days, but achieving desired blood glucose control may take several weeks.
Continue using metformin ER as prescribed, even if you start feeling better. Regular use according to your prescription is crucial for managing blood sugar levels.
While metformin ER is primarily used for treating type 2 diabetes, healthcare providers may prescribe it off-label for other conditions like polycystic ovary syndrome (PCOS) or weight management in patients with overweight or obesity.
Discuss any alternative uses of metformin ER with your healthcare provider.
Metformin ER is available in the following dosage forms:
Metformin ER is a prescription medication. You will need a valid prescription from a licensed healthcare provider to obtain this medication.
The use of metformin ER can lead to various side effects in some individuals.
Common mild side effects of metformin ER use include:
More severe side effects include:
If you experience any severe or concerning side effects while taking metformin ER, contact your healthcare provider right away.
Tell your healthcare provider about any existing medical conditions, allergies, or other medications you are taking before starting treatment with metformin ER. This includes prescription drugs, over-the-counter medications, and dietary supplements, as they may interact with metformin ER.
Tell your provider if you are taking these medications or supplements:
You should also mention medical conditions such as:
If you are pregnant, planning to become pregnant, or breastfeeding, discuss the potential risks and benefits of using metformin ER with your healthcare provider.
Take metformin ER exactly as prescribed by your healthcare provider. Do not exceed the recommended dose or duration of treatment.
Metformin ER should be taken with a meal.
Your provider may prescribe metformin ER in conjunction with a reduced-calorie diet and increased physical activity to regulate blood sugar levels.
In case of a metformin ER overdose, seek medical attention immediately. Symptoms of overdose may include severe tiredness, weakness, slow heart rate, severe dizziness, or fainting. If you suspect an overdose, contact the poison control helpline at 1-800-222-1222 or call emergency services.
Metformin ER is available in the following forms:
The typical starting dose of metformin ER varies depending on individual patient factors. It is crucial to follow your healthcare provider's instructions regarding dosage and administration.
For type 2 diabetes:
The dosage may be adjusted based on the response and tolerance to the medication. Your healthcare provider will determine the most appropriate dose based on your medical history and your response to the medication.
Metformin ER should be taken as prescribed by your healthcare provider. Do not exceed the recommended dose or duration of treatment without consulting your provider.
If you have any questions about your dosage or need adjustments, contact your healthcare provider for guidance. If you want to talk to a provider right away, consider scheduling an online doctor appointment through a telehealth platform like Sesame.
If you miss a dose of metformin ER, take it as soon as you remember unless it is close to the time for your next scheduled dose. In that case, skip the missed dose and continue your regular dosing schedule. Do not double the dose to make up for a missed one.
Take metformin ER around the same time every day to maintain an even level of medication in your body.
Continue taking metformin ER as prescribed by your healthcare provider, even if you start feeling better. It's important to keep taking the medication as directed to manage your condition effectively.
Do not suddenly stop taking metformin ER as this can cause your blood sugar levels to become uncontrolled. Your healthcare provider will provide guidance if you need to stop taking it.
If you have any concerns or questions about your medication, discuss them with your healthcare provider for medical advice and recommendations.
Store metformin ER according to the instructions provided by your healthcare provider or pharmacist. Keep it at room temperature, away from light and moisture. Ensure the container is tightly closed and out of reach of children.
Do not use expired medication or medications that appear damaged or discolored. If you have any questions about storage, consult your healthcare provider or pharmacist for guidance.