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.

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.

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):

• Diarrhea
• Gas
• Headache
• Metallic taste in mouth
• Nausea

Keep out of the reach of children and pets.

Store at room temperature 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.

They need to know if you have any of these conditions:

• Anemia
• Dehydration
• Frequently drink alcohol
• Heart disease
• Kidney disease
• Liver disease
• Polycystic ovary syndrome
• Serious infection or injury
• Vomiting
• An unusual or allergic reaction to metformin, other medications, foods, dyes, or preservatives
• Pregnant or trying to get pregnant
• Breast-feeding

Do not take this medication with any of the following:

• Certain contrast medications given before X-rays, CT scans, MRI, or other procedures
• Dofetilide

This medication may also interact with the following:

• Acetazolamide
• Alcohol
• Certain antivirals for HIV or hepatitis
• Certain medications for blood pressure, heart disease, irregular heart beat
• Cimetidine
• Dichlorphenamide
• Digoxin
• Diuretics
• Estrogen or progestin hormones
• Glycopyrrolate
• Isoniazid
• Lamotrigine
• Memantine
• Methazolamide
• Metoclopramide
• Midodrine
• Niacin
• Phenothiazines like chlorpromazine, mesoridazine, prochlorperazine, thioridazine
• Phenytoin
• Ranolazine
• Steroid medications like prednisone or cortisone
• Stimulant medications for attention disorders, weight loss, or to stay awake
• Thyroid medications
• Topiramate
• Trospium
• Vandetanib
• Zonisamide

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.

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, and carry a card that describes your disease and details of your medication and dosage times.

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.