What is the most important information I should know about metformin?
You should not use this medicine if you have severe kidney disease or diabetic ketoacidosis (call your doctor for treatment).
If you need to have any type of x-ray or CT scan using a dye that is injected into your veins, you will need to temporarily stop taking metformin.
This medicine may cause a serious condition called lactic acidosis. Get emergency medical help if you have even mild symptoms such as: muscle pain or weakness, numb or cold feeling in your arms and legs, trouble breathing, stomach pain, nausea with vomiting, slow or uneven heart rate, dizziness, or feeling very weak or tired.
What is metformin?
Metformin is an oral diabetes medicine that helps control blood sugar levels.
Metformin used together with diet and exercise to improve blood sugar control in adults with type 2 diabetes mellitus. Metformin is sometimes used together with insulin or other medications, but metformin is not for treating type 1 diabetes.
Metformin may also be used for purposes not listed in this medication guide.
What should I discuss with my healthcare provider before taking metformin?
You should not use metformin if you are allergic to it, or if you have:
- severe kidney disease; or
- metabolic or diabetic ketoacidosis (call your doctor for treatment).
If you need to have any type of x-ray or CT scan using a dye that is injected into your veins, you will need to temporarily stop taking metformin.
To make sure metformin is safe for you, tell your doctor if you have ever had:
- kidney disease (your kidney function may need to be checked before you take this medicine);
- high ketone levels in your blood or urine;
- heart disease, congestive heart failure;
- liver disease; or
- if you also use insulin, or other oral diabetes medications.
Some people taking metformin develop a serious condition called lactic acidosis. This may be more likely if you have liver or kidney disease, congestive heart failure, surgery, a heart attack or stroke, a severe infection, if you are 65 or older, if you are dehydrated, or if you drink a lot of alcohol. Talk with your doctor about your risk.
Follow your doctor's instructions about using this medicine if you are pregnant. Blood sugar control is very important during pregnancy, and your dose needs may be different during each trimester of pregnancy. Tell your doctor if you become pregnant while taking metformin.
It is not known whether metformin passes into breast milk or if it could harm a nursing baby. You should not breast-feed while using this medicine.
Metformin should not be given to a child younger than 10 years old. Some forms of metformin are not approved for use by anyone younger than 18 years old.
How should I take metformin?
Follow all directions on your prescription label. Your doctor may occasionally change your dose. Do not use this medicine in larger or smaller amounts or for longer than recommended.
Take metformin with a meal, unless your doctor tells you otherwise. Some forms of metformin are taken only once daily with the evening meal. Follow your doctor's instructions.
Do not crush, chew, or break an extended-release tablet. Swallow it whole.
Measure liquid medicine with the dosing syringe provided, or with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.
Some tablet forms of metformin are made with a shell that is not absorbed or melted in the body. Part of the tablet shell may appear in your stool. This is a normal side effect of metformin and will not make the medication less effective.
Your blood sugar will need to be checked often, and you may need other blood tests at your doctor's office.
Low blood sugar (hypoglycemia) can happen to everyone who has diabetes. Symptoms include headache, hunger, sweating, irritability, dizziness, nausea, fast heart rate, and feeling anxious or shaky. To quickly treat low blood sugar, always keep a fast-acting source of sugar with you such as fruit juice, hard candy, crackers, raisins, or non-diet soda.
Your doctor can prescribe a glucagon emergency injection kit to use in case you have severe hypoglycemia and cannot eat or drink. Be sure your family and close friends know how to give you this injection in an emergency.
Blood sugar levels can be affected by stress, illness, surgery, exercise, alcohol use, or skipping meals. Ask your doctor before changing your dose or medication schedule.
Metformin is only part of a complete treatment program that may also include diet, exercise, weight control, and special medical care. Follow your doctor's instructions very closely.
Your doctor may have you take extra vitamin B12 while you are taking metformin. Take only the amount of vitamin B12 that your doctor has prescribed.
Store at room temperature away from moisture, heat, and light.
What happens if I miss a dose?
Take the missed dose as soon as you remember (be sure to take the medicine with food). Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. An overdose of metformin may cause lactic acidosis, which may be fatal.
What should I avoid while taking metformin?
Avoid drinking alcohol. It lowers blood sugar and may increase your risk of lactic acidosis while taking metformin.
What are the possible side effects of metformin?
Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Some people develop lactic acidosis while taking metformin. Early symptoms may get worse over time and this condition can be fatal. Get emergency medical help if you have even mild symptoms such as:
- muscle pain or weakness;
- numb or cold feeling in your arms and legs;
- trouble breathing;
- feeling dizzy, light-headed, tired, or very weak;
- stomach pain, nausea with vomiting; or
- slow or uneven heart rate.
Common side effects may include:
- low blood sugar;
- nausea, upset stomach; or
- diarrhea.
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.
What other drugs will affect metformin?
Sometimes it is not safe to use certain medications at the same time. Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective.
Other drugs may interact with metformin, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.
Where can I get more information?
Your pharmacist can provide more information about metformin.
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.
Copyright 1996-2018 Cerner Multum, Inc. Version: 13.01. Revision date: 9/21/2017.
