Metformin Tablet - Uses, Side Effects, Precautions and FAQs
Uses
Metformin is used with a proper diet and exerciseprogram and possibly with other medications to control high blood sugar. It is used in patients with type 2 diabetes. Controlling high blood sugar helps prevent kidney damage, blindness, nerve problems, loss of limbs, and sexual function problems. Proper control of diabetes may also lessen your risk of a heart attack or stroke. Metformin works by helping to restore your body's proper response to the insulin you naturally produce. It also decreases the amount of sugar that your liver makes and that your stomach/intestinesabsorb.
Side Effects
Metformin side effects
Get emergency medical help if you have signs of an allergic reaction to metformin: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Some people using this medicine develop lactic acidosis, which can be fatal. Get emergency medical help if you have even mild symptoms such as:
unusual muscle pain;
feeling cold;
trouble breathing;
feeling dizzy, light-headed, tired, or very weak;
stomach pain, vomiting; or
slow or irregular heart rate.
Common metformin side effects may include:
low blood sugar;
nausea, upset stomach; or
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
Precautions
The metformin dosage your doctor prescribes will depend on several factors. These include:
- the type and severity of the condition you’re using metformin to treat
- your age
- the form of metformin you take
- other medical conditions you may have
Typically, your doctor will start you on a low dosage and adjust it over time to reach the dosage that’s right for you. They’ll ultimately prescribe the smallest dosage that provides the desired effect.
The following information describes dosages that are commonly used or recommended. However, be sure to take the dosage your doctor prescribes for you. Your doctor will determine the best dosage to suit your needs.
Forms and strengths
Generic: Metformin
- Form: immediate-release oral tablet
- Strengths: 500 mg, 850 mg, 1,000 mg
- Form: extended-release oral tablet
- Strengths: 500 mg, 750 mg, 1,000 mg
Brand: Fortamet
- Form: extended-release oral tablet
- Strengths: 1,000 mg
Brand: Glumetza
- Form: extended-release oral tablet
- Strengths: 500 mg, 1,000 mg
Find answers to some commonly asked questions about metformin oral tablet.
Is metformin used for PCOS or fertility problems? If so, what’s the dosage?
Metformin is not approved to treat polycystic ovary syndrome (PCOS) or fertility problems.
PCOS is a hormone condition that can occur in females.* It may cause irregular periods and also lead to fertility problems. Additionally, with PCOS, you can have insulin resistance (a condition in which your body doesn’t respond to insulin like usual). Insulin resistance can contribute to certain symptoms of PCOS, such as weight gain.
In some cases, metformin is used off-label to treat PCOS or help with fertility problems. (With off-label use, a drug is used for a condition other than what it’s approved to treat.)
The drug can reduce insulin resistance so that your body can use insulin properly. This can lower your blood sugar level. And in people with PCOS, normal menstrual cycles may occur, decreasing fertility issues.
Because metformin is not approved to treat PCOS or fertility problems, there’s no approved dosage of the drug for these purposes.
If you’re interested in taking metformin to treat PCOS or fertility problems, talk with your doctor. They may discuss this treatment option with you and recommend a proper dose.
* In this article, we use the term “female” to refer to someone’s sex assigned at birth. For information about the difference between sex and gender, see this article.
How does metformin work? And how long does it stay in your system?
Metformin works to treat type 2 diabetes in certain people. With type 2 diabetes, your body can’t regulate your blood sugar level like usual.
Normally, your body regulates your blood sugar level by releasing insulin. Insulin is a hormone that helps your body use sugar as energy. But people with type 2 diabetes may not make enough insulin, or they may have insulin resistance. (With insulin resistance, your body doesn’t respond as well as usual to insulin.) So the hormone doesn’t work like it should, resulting in increased blood sugar levels.
Metformin works in these ways to treat type 2 diabetes:
- decreases blood sugar that’s made by your liver
- decreases your body’s absorption of sugar from your food
- makes your body more sensitive to insulin, so that the hormone works better to decrease your blood sugar level
How long a drug stays in your system is related to the drug’s half-life. The half-life of a drug tells how long it takes for your body to get rid of half of a dose of the drug.
The half-life of metformin is about 6 hours and 12 minutes. So after this length of time, your body has cleared half of a dose of the drug. In general, it takes about four to five half-lives for your body to clear an entire dose of a drug.
Studies show that your body gets rid of about 90% of a dose of metformin through your kidneys within 24 hours of taking it. This is why it is important to take metformin doses every day.
Are there alternatives to metformin? What about natural alternatives such as berberine?
Yes, there are other treatment options besides metformin for type 2 diabetes. But metformin is recommended in the American Diabetes Association’s guidelines as the preferred first treatment option for people with type 2 diabetes. In some cases, though, people may be allergic to metformin. Or they may have side effects from the medication.
Many other options for diabetes treatment are available in addition to metformin. This includes other drugs taken by mouth, drugs given by injection, and even certain natural supplements.
Examples of other drugs taken by mouth that can be used for type 2 diabetes include:
- sitagliptin (Januvia)
- linagliptin (Tradjenta)
- canagliflozin (Invokana)
- dapagliflozin (Farxiga)
- pioglitazone (Actos)
- glimepiride (Amaryl)
- glipizide (Glucotrol)
Examples of drugs given by injection that can be used for type 2 diabetes include:
- dulaglutide (Trulicity)
- semaglutide (Ozempic)
- insulin lispro (Humalog)
- insulin aspart (Novolog)
- insulin glargine (Lantus)
Additionally, some natural supplements may be beneficial in decreasing blood sugar levels. But keep in mind that supplements do not go through the same studies as prescription drugs. And they’re not approved for use by the Food and Drug Administration (FDA).
It’s not known how well supplements may work to treat diabetes, if at all. Examples of some supplements that may be used for diabetes include:
Before starting any supplements, be sure to talk with your doctor or pharmacist. Although supplements are available over the counter, they may interact with your prescription medications. So always check with your doctor before taking one.
If you’re interested in using a treatment for type 2 diabetes other than metformin, talk with your doctor.
