Metformin (By mouth)
Metformin Hydrochloride (met-FOR-min hye-droe-KLOR-ide)
Used with diet and exercise to control blood sugar in patients with type 2 diabetes. May be used alone or with other medicines.
Glucophage, Glucophage XR, Riomet, Appformin, Appformin-D, Fortamet, Glumetza
There may be other brand names for this medicine.
When This Medicine Should Not Be Used
You should not use this medicine if you have had an allergic reaction to metformin, or if you have type 1 diabetes or diabetic acidosis (ketones in the blood). You should not use this medicine if you have severe kidney problems or metabolic acidosis (extra acid in the blood). Do not use this medicine if you are going to have an x-ray procedure with an injection of contrast dyes in your vein. The extended-release tablet form of this medicine should not be given to anyone younger than 18 years of age.
How to Use This Medicine
Liquid, Tablet, Long Acting Tablet
- Your doctor will tell you how much of this medicine to use and how often. Your dose may need to be changed several times in order to find out what works best for you. Do not use more medicine or use it more often than your doctor tells you to.
- It is best to take this medicine with food or milk.
- It may take up to 2 weeks for this medicine to start lowering your blood sugar. It may be 2 to 3 months before you get the full effect from the medicine.
- Swallow the extended-release tablet whole. Do not crush, break, or chew it. Tell your doctor if you have trouble swallowing the tablets whole.
- While taking the extended-release form of this medicine, part of the tablet may pass into your stools. This is normal and is nothing to worry about.
- Measure the oral liquid medicine with a marked measuring spoon, oral syringe, or medicine cup.
- Carefully follow your doctor's instructions about any special diet.
- Drink extra fluids so you will pass more urine while you are using this medicine. This will keep your kidneys working well and help prevent kidney problems.
- Use only the brand of this medicine that your doctor prescribed. Different brands may not work the same way.
- This medicine comes with patient instructions. Read and follow these instructions carefully. Ask your doctor or pharmacist if you have any questions.
If a dose is missed:
- If you miss a dose or forget to use your medicine, use it as soon as you can. If it is almost time for your next dose, wait until then to use the medicine and skip the missed dose. Do not use extra medicine to make up for a missed dose.
How to Store and Dispose of This Medicine
- Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
- Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
- Keep all medicine away from children and never share your medicine with anyone.
Drugs and Foods to Avoid
Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.
- Make sure your doctor knows if you are using other medicines to treat your diabetes, such as insulin.
- Make sure your doctor knows if you also use digoxin (Lanoxin®), isoniazid (Nydrazid®), morphine, nicotinic acid (Nicobid®, Nicolar®), phenytoin (Dilantin®), procainamide (Procanbid®, Pronestyl®), quinidine (Quinidex®), quinine, ranitidine (Zantac®), trimethoprim (Bactrim®, Primsol®, Proloprim®, Septra®), or vancomycin (Vancocin®, Vancoled®). Tell your doctor if you are using acetazolamide (Diamox®), dichlorphenamide (Daranide®), topiramate (Topamax®), or zonisamide (Zonegram®).
- Tell your doctor if you are also using diuretics or "water pills" (such as amiloride, furosemide, hydrochlorothiazide [HCTZ], triamterene, Dyrenium®, Lasix®, or Midamor®), a steroid medicine (such as dexamethasone, prednisolone, prednisone, or Medrol®), a phenothiazine medicine (such as prochlorperazine, Compazine®, Mellaril®, Phenergan®, Thorazine®, or Trilafon®), thyroid replacement (such as levothyroxine, liothyronine, Cytomel®, or Synthroid®), estrogen hormones (such as Premarin®), or birth control pills. Make sure your doctor knows if you use heart or blood pressure medicine (such as amlodipine, metoprolol, nifedipine, verapamil, Adalat®, Cardizem®, Lopressor®, Lotrel®, Norvasc®, Procardia®, Tenormin®, or Tiazac®).
- Do not drink alcohol while you are using this medicine.
Warnings While Using This Medicine
- Make sure your doctor knows if you are pregnant or breastfeeding, or if you have any kind of heart or blood vessel disease, heart failure, blood circulation problems, or a history of a heart attack. Also tell your doctor if you have kidney disease, liver disease, anemia, an adrenal gland disorder, a pituitary gland disorder, edema (problems with fluid retention or swelling), or condition called vitamin B12 deficiency. Tell your doctor if you are drinking too much alcohol.
- This medicine may cause a rare, but serious condition called lactic acidosis in some people. Call your doctor right away if you get sick, or if you have unusual tiredness, weakness, muscle pain, stomach pain, trouble breathing, fever, or nausea. Your risk of getting this condition is higher the longer you take this medicine.
- Make sure any doctor or dentist who treats you knows that you are using this medicine. You may need to stop using this medicine several days before having surgery or medical tests.
- This medicine may interact with the dye used for an X-ray or CT scan. Your doctor should advise you to stop taking it before you have any medical exams or diagnostic tests that might cause less urine output than usual. You may be advised to start taking the medicine again 48 hours after the exams or tests if your kidney function is tested and found to be normal.
- Your doctor will need to check your blood or urine at regular visits while you are using this medicine. Be sure to keep all appointments.
- This medicine is only part of a complete program for controlling diabetes. You can also help yourself by eating a healthy diet, watching your weight, and getting regular exercise.
Possible Side Effects While Using This Medicine
Call your doctor right away if you notice any of these side effects:
- Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
- Chest discomfort, or slow or uneven heartbeat.
- Dry mouth, increased thirst, or decrease in how much you urinate.
- Extreme weakness, tiredness, or confusion.
- Fever or chills.
- Lightheadedness, dizziness, or fainting.
- Rapid breathing, trouble breathing, or nausea and vomiting.
- Unusual muscle weakness or pain.
- Unusual tiredness or weakness.
If you notice these less serious side effects, talk with your doctor:
- Diarrhea, gas, indigestion, or stomach pain or upset.
- Metallic taste in your mouth.
If you notice other side effects that you think are caused by this medicine, tell your doctor
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088
- Last Reviewed on 06/12/2013
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This page was last updated: June 18, 2013