metformin
Immediate-release metformin is an oral diabetes medication. It's approved for people 10 years of age and older with Type 2 diabetes. The medication belongs to the drug class called biguanides. It works best to lower blood sugar levels with a diabetes-friendly diet and exercise plan. Immediate-release metformin comes as a tablet and an oral solution. You take this medication by mouth usually two to three times a day. It's recommended to take each dosage with food to help lessen side effects like diarrhea and nausea.
What is Metformin?
What is Metformin used for?
Type 2 diabetes in people ages 10 years and older
How Metformin works
Metformin is a type of diabetes medication called a biguanide. It helps lower blood sugar in a few ways.
It stops your liver from making sugar.
It lowers the amount of sugar your body absorbs from food and drinks.
It helps your body use its natural insulin better.
Drug Facts
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What are the side effects of Metformin?
Common Side Effects
- Diarrhea (53%)
- Nausea or vomiting (26%)
- Gas (12%)
- Weakness (9%)
Other Side Effects
- Indigestion
- Stomach pain
- Headache
- Change in taste in the mouth
- Low vitamin B12 levels
Serious Side Effects
- High acid levels in the blood (lactic acidosis): very tired or weak, nausea, vomiting, fast heartbeat, fast breathing, confusion
Source: DailyMed
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The following side effects have also been reported
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
More common
Abdominal or stomach discomfort
cough or hoarseness
decreased appetite
fast or shallow breathing
fever or chills
general feeling of discomfort
lower back or side pain
muscle pain or cramping
painful or difficult urination
sleepiness
Less common
blurred vision
chest discomfort
cold sweats
coma
confusion
cool, pale skin
difficult or labored breathing
dizziness
fast, irregular, pounding, or racing heartbeat or pulse
feeling of warmth
headache
increased hunger
increased sweating
nervousness
nightmares
redness of the face, neck, arms, and occasionally, upper chest
seizures
shakiness
slurred speech
tightness in the chest
unusual tiredness or weakness
Rare
Behavior change similar to being drunk
difficulty with concentrating
drowsiness
lack or loss of strength
restless sleep
unusual sleepiness
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
More common
Acid or sour stomach
belching
bloated
excess air or gas in the stomach or intestines
full feeling
indigestion
loss of appetite
metallic taste in the mouth
passing of gas
stomachache
stomach upset or pain
vomiting
Less common
Abnormal stools
bad, unusual, or unpleasant (after) taste
change in taste
difficulty with moving
discoloration of the fingernails or toenails
flu-like symptoms
joint pain
rash
stuffy or runny nose
swollen joints
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Pros and cons of Metformin
Pros
One of the first-choice options for Type 2 diabetes
Works well at lowering blood sugar levels (can lower your A1C by up to 1.5% in a few months)
Available as a liquid for people who have trouble swallowing tablets
Cons
Typically need to take a couple times per day
Can cause stomach upset, including diarrhea, nausea, gas, and stomach cramping
Not a good choice for people with severe kidney problems
Not recommended for people with liver problems
Pharmacist tips for Metformin
Take metformin at the same time(s) every day with a meal. Taking it with food will help prevent stomach upset from the medication. This can include diarrhea and nausea.
Swallow the metformin tablet whole. Talk to your prescriber if you have trouble swallowing it whole. They might discuss the option to switch to the liquid form of the medication.
Be sure to drink enough fluids to stay hydrated. This is very important if you have diarrhea or vomit after taking metformin. Drinking fluids can help prevent dehydration from these side effects.
Check your blood sugar regularly as instructed by your care team. Keep track of your readings and share them with your care team. This helps them see how well the metformin is working for you and see if your treatment plan needs to be adjusted.
Tell your care team if you're having surgery or an imaging test done. Also let them know if you've had one in the past 2 days. Some procedures use contrast dye that can interact with metformin. It can affect your kidneys for a short time and raise your risk of lactic acidosis, which can be serious. Your care team will let you know if you need to stop metformin before your procedure and when to start it again.
It's possible to have low blood sugar, especially if you take metformin with insulin or medications like glipizide. If you feel shaky, nervous, or confused or if you have a fast heartbeat, check your blood sugar to see if it's low. Be sure you know how to treat it and when to call 911 if your blood sugar gets low.
It's important to eat a balanced diet and stay active while taking metformin. Along with the medication, healthy eating and exercise helps keep your blood sugar under control. Talk to your healthcare team to come up with a diet and exercise plan that works best for you.
Tips for the metformin liquid:
To measure out the liquid, be sure to use the dosing cup that comes with the medication. Or, use a dosing cup or oral syringe from the pharmacy. Don't use household measuring cups or spoons because they aren't accurate and you could take the wrong dose with them.
Keep the metformin liquid at room temperature (up to 86ºF).
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Frequently asked questions about Metformin
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What are the risks and warnings for Metformin?
Metformin can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Lactic acidosis
Risk factors: Kidney problems | Liver problems | Heart problems | Age 65 or older | Drinking a lot of alcohol | People with food or fluid restrictions | Using contrast dye for surgery or other procedures
Although it's rare, metformin can cause a serious condition called lactic acidosis (too much lactic acid in the blood). This can be serious and life-threatening. Tell your prescriber about your health problems and all the medications you take before starting metformin. They can check if you're at risk of lactic acidosis.
Call your care team right away if you have fast breathing, shortness of breath, an irregular heartbeat, a very upset stomach, or muscle pain. Also call if you feel very sleepy, tired, weak, dizzy, or cold. These could be signs of lactic acidosis. Your care team can help manage and treat this condition.
Low vitamin B12 levels
Risk factors: Long-term use of metformin | Lower than average calcium absorption | Lower than average vitamin B12 absorption
Metformin can cause low vitamin B12 levels. This can lead to anemia (a low red blood cell count). Your prescriber might ask for blood tests every few years during treatment to check for low vitamin B12 and anemia.
Reach out to your care team if you feel tired, short of breath, dizzy, or "pins and needles" in your hands or feet. These might be signs of vitamin B12 deficiency. If blood tests show that your levels are low, your prescriber might recommend a vitamin B12 supplement to get your levels back up.
Low blood sugar (hypoglycemia) when taken with certain other diabetes medications
Risk factors: Using insulin | Taking sulfonylureas like glipizide
Your low blood sugar can drop too low if you take metformin with certain other diabetes medications. Particular examples include insulin and sulfonylureas like glipizide. Very low blood sugar can be dangerous.
If you need insulin or a sulfonylurea with metformin, talk to your prescriber about how to lower your risk of very low blood sugar. They might need to adjust the dose of your diabetes medications.
To be safe, be sure you know how to spot and treat low blood sugar. Look out for shakiness, hunger, confusion, or weakness. You also might be nervous or anxious, have a fast heartbeat, or sweat. Carry fast-acting sugars with you to get your blood sugar back up and let your care team know if this happens. Talk to your care team if you're worried about low blood sugar while taking metformin.
Metformin dosage forms
Typical dosing for Metformin
Metformin is available as an immediate-release tablet and a 100 mg/mL liquid.
Adults: The typical starting dose is 500 mg by mouth twice per day or 850 mg by mouth once per day. Your prescriber will adjust your dose depending on how well it's helping with your blood sugar and if you have side effects that bother you. The maximum dose is 850 mg by mouth three times per day.
Children ages 10 years and older: The typical starting dose is 500 mg by mouth twice per day. The prescriber will adjust the dose based on your child's blood sugar levels and any side effects. The maximum dose is 1,000 mg by mouth twice per day.
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Interactions between Metformin and other drugs
More on Metformin interactions
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
- Acetrizoic Acid
- Diatrizoate
- Ethiodized Oil
- Iobenzamic Acid
- Iobitridol
- Iocarmic Acid
- Iocetamic Acid
- Iodamide
- Iodipamide
- Iodixanol
- Iodohippuric Acid
- Iodopyracet
- Iodoxamic Acid
- Ioglicic Acid
- Ioglycamic Acid
- Iohexol
- Iomeprol
- Iopamidol
- Iopanoic Acid
- Iopentol
- Iophendylate
- Iopromide
- Iopronic Acid
- Ioseric Acid
- Iosimide
- Iotasul
- Iothalamate
- Iotrolan
- Iotroxic Acid
- Ioxaglate
- Ioxitalamic Acid
- Ipodate
- Metrizamide
- Metrizoic Acid
- Tyropanoate Sodium
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Aspirin
- Balofloxacin
- Besifloxacin
- Bupropion
- Capmatinib
- Chloroquine
- Ciprofloxacin
- Dasabuvir
- Dofetilide
- Dolutegravir
- Enoxacin
- Fleroxacin
- Flumequine
- Gatifloxacin
- Gemifloxacin
- Hydroxychloroquine
- Ioversol
- Lanreotide
- Levofloxacin
- Lomefloxacin
- Moxifloxacin
- Nadifloxacin
- Norfloxacin
- Octreotide
- Ofloxacin
- Ombitasvir
- Paritaprevir
- Pasireotide
- Pazufloxacin
- Pefloxacin
- Pioglitazone
- Prulifloxacin
- Ritonavir
- Rufloxacin
- Sitagliptin
- Sparfloxacin
- Tafenoquine
- Thioctic Acid
- Tosufloxacin
- Vandetanib
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Acebutolol
- Atenolol
- Betaxolol
- Bisoprolol
- Bitter Melon
- Carteolol
- Carvedilol
- Celiprolol
- Colesevelam
- Esmolol
- Fenugreek
- Furazolidone
- Glucomannan
- Guar Gum
- Iproniazid
- Isocarboxazid
- Labetalol
- Levobunolol
- Linezolid
- Methylene Blue
- Metipranolol
- Metoprolol
- Moclobemide
- Nadolol
- Nebivolol
- Nialamide
- Oxprenolol
- Patiromer
- Penbutolol
- Phenelzine
- Pindolol
- Practolol
- Procarbazine
- Propranolol
- Psyllium
- Ranolazine
- Rasagiline
- Rifampin
- Safinamide
- Selegiline
- Sotalol
- Timolol
- Tranylcypromine
- Verapamil
How much does Metformin cost?
Metformin contraindications
Severe kidney problems
Short-term or long-term metabolic acidosis, including diabetic ketoacidosis (DKA), with or without coma
What are alternatives to Metformin?
Type 2 diabetes in people ages 10 years and older
Type 2 diabetes (in addition to diet and exercise) in people age 10 years and older
Lowering the risk of death due to heart problems in adults with Type 2 diabetes and heart disease
Lowering the risk of hospitalization and death due to heart problems in adults with heart failure
Lowering the risk of worsening kidney problems, hospitalization, and death due to heart problems in adults with chronic kidney disease (CKD)
What is the latest news about Metformin?
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