Metformin
PrescriptionWhat is Metformin?
Metformin is a prescription medication used to treat type 2 diabetes. It helps lower blood sugar levels by reducing glucose production in the liver. This medication also improves how your body uses insulin, a hormone that helps sugar move from blood into cells.
Metformin belongs to a drug class called biguanides. It has been used safely for over 60 years and is often the first medication doctors prescribe for type 2 diabetes. Unlike some diabetes medications, metformin does not cause weight gain and may even help with modest weight loss.
This medication comes in regular tablets, extended-release tablets, and liquid forms. The extended-release version allows for once-daily dosing with fewer stomach side effects. Metformin requires a prescription and should be taken exactly as your doctor directs.
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Common uses
- Type 2 diabetes management in adults and children over 10 years old
- Prediabetes prevention to delay or prevent type 2 diabetes development
- Polycystic ovary syndrome treatment to improve insulin resistance and menstrual cycles
- Weight management in patients with insulin resistance
- Gestational diabetes in some pregnant women when diet changes are not enough
How it works
Metformin works in three main ways to lower blood sugar. First, it reduces the amount of glucose your liver releases into your bloodstream. Second, it helps your muscles and other tissues absorb more sugar from your blood. Third, it slows down sugar absorption from the food you eat in your intestines.
The medication does not increase insulin production from your pancreas. This means it rarely causes dangerously low blood sugar when used alone. Metformin begins working within a few days, but you may need several weeks to see the full effects on your blood sugar levels.
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Dosage information
Adults typically start with 500 mg once or twice daily with meals. Your doctor may gradually increase your dose by 500 mg weekly based on your blood sugar levels. The maximum daily dose is usually 2,000 to 2,550 mg, divided into two or three doses. Extended-release forms are taken once daily with the evening meal. Always take metformin with food to reduce stomach upset. Your doctor determines your specific dose based on your kidney function, blood sugar levels, and response to treatment.
Side effects
- Nausea and stomach upset
- Diarrhea
- Gas and bloating
- Loss of appetite
- Metallic taste in mouth
- Vitamin B12 deficiency with long-term use
These side effects often improve after a few weeks as your body adjusts. Serious side effects are rare but include lactic acidosis, a dangerous buildup of lactic acid in the blood. Seek immediate medical attention if you experience unusual muscle pain, trouble breathing, severe nausea, extreme tiredness, or stomach pain with vomiting. Stop taking metformin and contact your doctor if you have severe or persistent diarrhea, vomiting, or fever.
Drug interactions
- Alcohol increases risk of lactic acidosis and low blood sugar
- Contrast dye used in CT scans and X-rays may require temporarily stopping metformin
- Carbonic anhydrase inhibitors like topiramate and acetazolamide increase lactic acidosis risk
- Insulin and other diabetes medications may increase low blood sugar risk
- Diuretics, corticosteroids, and thyroid medications may reduce metformin effectiveness
- Certain blood pressure medications may interact with metformin levels
- Not recommended for people with severe kidney disease or liver problems
Blood test monitoring
Regular blood testing is essential while taking metformin to ensure safe and effective treatment. Your doctor will check your blood sugar and hemoglobin A1c every 3 to 6 months to see how well the medication controls your diabetes. Kidney function tests, specifically eGFR or estimated glomerular filtration rate, should be checked before starting metformin and at least yearly. These tests are important because metformin is removed from your body through the kidneys. Your doctor may also monitor vitamin B12 levels, especially if you take metformin long-term, since the medication can reduce B12 absorption. Rite Aid offers blood testing services that include glucose, hemoglobin A1c, and kidney function markers to help you stay on top of your diabetes management.
Related blood tests
Taking Metformin? Monitor your levels.
- Track how your body responds
- Catch side effects early with blood work
- Share results with your doctor
Frequently asked questions
Yes, metformin is available at Rite Aid Pharmacy with a valid prescription from your doctor. Rite Aid pharmacy services are returning soon and will offer both brand name and generic versions of metformin. You can submit your prescription information now to receive updates when full pharmacy services resume in your area.
Metformin begins lowering blood sugar within a few days of starting treatment. However, it may take 2 to 3 weeks to see the full effects on your blood sugar levels. Your doctor will likely check your hemoglobin A1c after 3 months to evaluate how well metformin is working for your diabetes management.
Yes, always take metformin with meals to reduce stomach upset and nausea. Taking this medication with food helps minimize common digestive side effects like diarrhea and stomach pain. If you take extended-release metformin, take it with your evening meal unless your doctor directs otherwise.
You need regular monitoring of blood glucose, hemoglobin A1c, and kidney function tests while taking metformin. Your doctor will check these levels before starting the medication and every 3 to 6 months during treatment. Rite Aid offers blood testing services that measure over 200 biomarkers including glucose, hemoglobin A1c, and kidney function markers to help track your diabetes management.
Metformin alone rarely causes dangerously low blood sugar, called hypoglycemia. However, your risk increases if you take metformin with insulin or other diabetes medications. Drinking alcohol, skipping meals, or exercising more than usual can also increase low blood sugar risk. Talk to your doctor about recognizing and treating low blood sugar symptoms.
If you miss a dose of metformin, take it as soon as you remember with food. If it is almost time for your next scheduled dose, skip the missed dose and continue your regular dosing schedule. Never take two doses at once to make up for a missed dose, as this increases side effect risk.
Metformin may lead to modest weight loss of 4 to 6 pounds in some people with type 2 diabetes. Unlike some diabetes medications that cause weight gain, metformin is weight neutral or may slightly reduce weight. The weight loss effect varies from person to person and is not guaranteed for everyone taking the medication.
You should limit or avoid alcohol while taking metformin. Drinking alcohol increases your risk of lactic acidosis, a rare but serious side effect. Alcohol also increases the risk of low blood sugar and can worsen metformin's digestive side effects. Talk to your doctor about safe alcohol limits if you choose to drink.
Your kidneys remove metformin from your body, so proper kidney function is essential for safe use. People with reduced kidney function have higher risk of lactic acidosis, a serious complication. Your doctor needs to know your eGFR or kidney filtration rate to determine if metformin is safe for you and what dose to prescribe.
Rite Aid offers blood testing that measures glucose, hemoglobin A1c, and kidney function markers you need while taking metformin. The service costs $349 per year and includes 2 tests annually measuring over 200 biomarkers. Regular testing helps you and your doctor see how well metformin controls your diabetes and ensures the medication remains safe for your kidneys.