METFORMIN (met FOR min) treats type 2 diabetes. It controls blood sugar (glucose) and helps your body use insulin effectively. Changes to diet and exercise are often combined with this medication.
What should I tell my care team before I take this medication?
They need to know if you have any of these conditions:
Dehydration
Frequently drink alcohol
Have had diabetic ketoacidosis (DKA)
Having a CT or X-ray scan
Having surgery
Heart attack
Heart disease
Infection
Irregular menstrual cycles
Kidney disease
Liver disease
Low levels of calcium in your blood
Low levels of vitamin B in your blood
Stroke
An unusual or allergic reaction to metformin, other medications, foods, dyes, or preservatives
Pregnant or trying to get pregnant
Breastfeeding
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 agents used before CT, MRI, or X-ray scans
This medication may also interact with the following:
Acetazolamide
Alcohol
Cimetidine
Dichlorphenamide
Dolutegravir
Ranolazine
Topiramate
Vandetanib
Zonisamide
Some medications may affect your blood sugar levels or hide the symptoms of low blood sugar (hypoglycemia). Talk with your care team about all the medications you take. They may suggest checking your blood sugar levels more often.
Medications that may affect your blood sugar levels include:
Alcohol
Certain antibiotics, such as ciprofloxacin, levofloxacin, sulfamethoxazole; trimethoprim
Certain medications for blood pressure or heart disease, such as benazepril, enalapril, lisinopril, losartan, valsartan
Certain medications for mental health conditions, such as fluoxetine or olanzapine
Diuretics, such as hydrochlorothiazide (HCTZ)
Estrogen and progestin hormones
Other medications for diabetes
Steroid medications, such as prednisone or cortisone
Testosterone
Thyroid hormones
Medications that may mask symptoms of low blood sugar include:
Beta-blockers, such as atenolol, metoprolol, propranolol
Clonidine
Guanethidine
Reserpine
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 and fatigue
Low vitamin B12 level—pain, tingling, or numbness in the hands or feet, muscle weakness, dizziness, confusion, trouble concentrating
Side effects that usually do not require medical attention (report these to your care team if they continue or are bothersome):
Diarrhea
Gas
Headache
Metallic taste in mouth
Nausea
What should I watch for while using this medication?
Visit your care team for regular checks on your progress. Tell your care team if your symptoms do not start to get better or if they get worse.
You may need blood work done while you are taking this medication. Your care team will monitor your HbA1C (A1C). This test shows what your average blood sugar (glucose) level was over the past 2 to 3 months.
Know the symptoms of low blood sugar and know how to treat it. Always carry a source of quick sugar with you. Examples include hard sugar candy or glucose tablets. Make sure others know that you can choke if you eat or drink if your blood sugar is too low and you are unable to care for yourself. Get medical help at once.
Tell your care team if you have high blood sugar. Your medication dose may change if your body is under stress. Some types of stress that may affect your blood sugar include fever, infection, and surgery.
Wear a medical ID bracelet or chain. Carry a card that describes your condition. List the medications and doses you take on the card.
Make sure you stay hydrated while taking this medication. Drink water often. Eat fruits and veggies that have a high water content. Drink more water when it is hot or you are active. Talk to your care team right away if you have fever, infection, vomiting, diarrhea, or if you sweat a lot while taking this medication. The loss of too much body fluid may make it dangerous for you to take this medication.
Tell your care team you are taking this medication before you have surgery or an imaging scan, such as a CT or X-ray. You may need to stop taking this medication for a while before and after the procedure. Your care team will tell you when to stop and when to start taking it again.
Drinking alcohol with this medication can increase the risk of side effects.
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.
Make sure you get enough vitamin B12 while you are taking this medication. Discuss the foods you eat and the vitamins you take with your care team.
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.
Where should I keep my medication?
Keep out of the reach of children and pets.
Store at room temperature between 20 and 25 degrees C (68 and 77 degrees F). Get rid of any unused medication after the expiration date.
To get rid of medications that are no longer needed or have 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.
