Metformin is the most commonly prescribed medicine for type 2 diabetes. It lowers blood sugar without usually causing very low sugar levels, and it does not cause weight gain.
What Is Metformin Used For?
- Type 2 diabetes
- Prediabetes, when a doctor advises it
- Polycystic ovary syndrome (PCOS), as an off-label use
How Does Metformin Work?
Metformin lowers the amount of sugar your liver makes and helps your body respond better to insulin. It also reduces how much sugar your gut absorbs.
General Dosage Information
This is general information only. Your doctor sets the right dose for you, so follow your prescription and the label.
- Doctors usually start with 500 mg once or twice a day with meals and raise the dose slowly.
- The usual maximum is about 2,000 mg to 2,550 mg a day, depending on the form.
- Extended-release tablets are taken once a day, usually with the evening meal. Swallow them whole.
Side Effects of Metformin
Common Side Effects
- Nausea, diarrhea, and stomach upset, which often improve with time
- Metallic taste
- Loss of appetite
- Low vitamin B12 with long-term use
Serious Side Effects
Call your doctor or get emergency help if you notice:
- Lactic acidosis, which is rare: unusual muscle pain, trouble breathing, extreme tiredness, stomach pain, or feeling cold
- Signs of very low vitamin B12, such as numbness or tingling in the hands and feet
Who Should Be Cautious?
- People with kidney problems, because the dose may need to change or the drug may be unsafe
- People with liver disease or heavy alcohol use
- People having an X-ray scan with contrast dye, who may need to pause it
- People with heart failure or serious infection
- Pregnant women should ask their doctor
Drug Interactions
Tell your doctor and pharmacist about every medicine and supplement you take. Examples of important interactions include:
- Alcohol: it raises the risk of lactic acidosis.
- Iodinated contrast dye: your doctor may ask you to stop metformin before the scan.
- Cimetidine and topiramate: they can raise metformin levels.
- Diuretics and corticosteroids: they can raise blood sugar.
Storage and Precautions
- Store it at room temperature, away from heat, light, and moisture.
- Keep it out of the reach of children.
Frequently Asked Questions
Does metformin help with weight loss?
It may cause small weight loss in some people, but it is not a weight-loss drug.
Can I stop it if my sugar is normal?
No. Ask your doctor first.
Can it cause low blood sugar?
Rarely on its own, but it can when combined with insulin or sulfonylureas.
Disclaimer: This article is for information only. It is not medical advice. Please talk to your doctor about your own health.