METFORMIN (met FOR min) treats type 2 diabetes. It controls blood sugar (glucose) and helps your body use insulin effectively. This medication is often combined with changes to diet and exercise.
What should I tell my care team before I take this medication?
They need to know if you have any of these conditions:
Frequently drink alcohol
Polycystic ovary syndrome
Serious infection or injury
An unusual or allergic reaction to metformin, other medications, foods, dyes, or preservatives
Pregnant or trying to get pregnant
How should I use this medication?
Take this medication by mouth with water. Take it as directed on the prescription label at the same time every day. Take it with food at the start of a meal. Do not cut, crush, or chew this medication. Swallow the tablets whole. Keep taking it unless your care team tells you to stop.
Talk to your care team about the use of this medication in children. Special care may be needed.
What if I miss a dose?
If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.
What may interact with this medication?
Do not take this medication with any of the following:
Certain contrast medications given before X-rays, CT scans, MRI, or other procedures
This medication may also interact with the following:
Certain antivirals for HIV or hepatitis
Certain medications for blood pressure, heart disease, irregular heart beat
Estrogen or progestin hormones
Phenothiazines, such as chlorpromazine, mesoridazine, prochlorperazine, thioridazine
Steroid medications, such as prednisone or cortisone
Stimulant medications for attention disorders, weight loss, or to stay awake
What side effects may I notice from receiving this medication?
Side effects that you should report to your care team as soon as possible:
Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat
High lactic acid level—muscle pain or cramps, stomach pain, trouble breathing, general discomfort or fatigue
Low vitamin B12 level—pain, tingling, or numbness in the hands or feet, muscle weakness, dizziness, confusion, difficulty concentrating
Side effects that usually do not require medical attention (report to your care team if they continue or are bothersome):
Metallic taste in mouth
What should I watch for while using this medication?
Visit your care team for regular checks on your progress.
A test called the HbA1C (A1C) will be monitored. This is a simple blood test. It measures your blood sugar control over the last 2 to 3 months. You will receive this test every 3 to 6 months.
Using this medication with insulin or a sulfonylurea may increase your risk of hypoglycemia. Learn how to check your blood sugar. Learn the symptoms of low and high blood sugar and how to manage them.
Always carry a quick-source of sugar with you in case you have symptoms of low blood sugar. Examples include hard sugar candy or glucose tablets. Make sure others know that you can choke if you eat or drink when you develop serious symptoms of low blood sugar, such as seizures or unconsciousness. They must get medical help at once.
Tell your care team if you have high blood sugar. You might need to change the dose of your medication. If you are sick or exercising more than usual, you might need to change the dose of your medication.
Do not skip meals. Ask your care team if you should avoid alcohol. Many nonprescription cough and cold products contain sugar or alcohol. These can affect blood sugar.
This medication may cause you to ovulate, which may increase your chances of becoming pregnant. Talk with your care team about contraception while you are taking this medication. Contact your care team if you think you might be pregnant.
The tablet shell for some brands of this medication does not dissolve. This is normal. The tablet shell may appear whole in the stool. This is not a cause for concern.
If you are going to need surgery, an MRI, CT scan, or other procedure, tell your health care provider that you are taking this medication. You may need to stop taking this medication before the procedure.
Wear a medical ID bracelet or chain. Carry a card that describes your condition. List the medications and doses you take on the card.
This medication may cause a decrease in folic acid and vitamin B12. You should make sure that you get enough vitamins while you are taking this medication. Discuss the foods you eat and the vitamins you take with your care team.
Where should I keep my medication?
Keep out of the reach of children and pets.
Store between 15 and 30 degrees C (59 and 86 degrees F). Protect from light. Get rid of any unused medication after the expiration date.
To get rid of medications that are no longer needed or expired:
Take the medication to a medication take-back program. Check with your pharmacy or law enforcement to find a location.
If you cannot return the medication, check the label or package insert to see if the medication should be thrown out in the garbage or flushed down the toilet. If you are not sure, ask your care team. If it is safe to put in the trash, empty the medication out of the container. Mix the medication with cat litter, dirt, coffee grounds, or other unwanted substance. Seal the mixture in a bag or container. Put it in the trash.
K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.
This information is educational only and should not be construed as specific instructions for individual patients nor as a substitute for medical advice, diagnosis or treatment. Talk to your health care provider or pharmacist about the information and instructions. K Health assumes no liability for any use or reliance on this information.