Metformin (glucophage)

Metformin is used alone or with other medications, including insulin, to treat type 2 (noninsulin-dependent) diabetes. Metformin helps to control the amount of glucose (sugar) in your blood. It decreases the amount of glucose you absorb from your food and the amount of glucose made by your liver. Metformin also increases your body's response to insulin, a natural substance that controls the amount of glucose in the blood. Metformin is not used to treat type 1 (insulin-dependent) diabetes.

How should this medicine be used?
Metformin comes as a tablet and an extended-release (long-acting) tablet to take by mouth. The regular tablet is usually taken with meals two or three times a day. The extended-release tablet is usually taken once daily with the evening meal. To help you remember to take metformin, take it around the same time(s) every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take metformin exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
Swallow metformin extended-release tablets whole; do not split, chew, or crush them.
Your doctor may start you on a low dose of metformin and gradually increase your dose not more often than once every 1 or 2 weeks. You will need to monitor your blood sugar carefully so your doctor will be able to tell how well metformin is working.
Metformin controls diabetes but does not cure it. Continue to take metformin even if you feel well. Do not stop taking metformin without talking to your doctor.

What special precautions should I follow?
Before taking metformin,
• tell your doctor and pharmacist if you are allergic to metformin or any other medications.
• tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking. Be sure to mention the medications listed in the IMPORTANT WARNING section and any of the following: amiloride (Midamor, Moduretic); antihistamines; beta-blockers such as atenolol (Tenormin), labetalol (Normodyne), metoprolol (Lopressor, Toprol XL), nadolol (Corgard), and propranolol (Inderal); calcium channel blockers such as amlodipine (Norvasc), diltiazem (Cardizem, Dilacor, Tiazac, others), felodipine (Lexxel, Plendil), isradipine (DynaCirc), nicardipine (Cardene), nifedipine (Adalat, Procardia), nimodipine (Nimotop), nisoldipine (Sular), and verapamil (Calan, Isoptin, Verelan); cimetidine (Tagamet); digoxin (Lanoxin, Lanoxicaps); furosemide (Lasix); hormone replacement therapy; insulin or other medications for diabetes; isoniazid (INH, Nydrazid); medications for asthma and colds; medications for mental illness and nausea such as fluphenazine (Prolixin), mesoridazine (Serentil), perphenazine (Trilafon), prochlorperazine (Compazine), promethazine (Phenergan), thioridazine (Mellaril), thiothixene (Navane), trifluoperazine (Stelazine), and triflupromazine (Vesprin); medications for thyroid disease; morphine (MS Contin, Roxanol, others); nicotinic acid; oral contraceptives (birth control pills); oral steroids such as dexamethasone (Decadron, Dexone), methylprednisolone (Medrol), and prednisone (Deltasone); phenytoin (Dilantin, Phenytek); procainamide (Procanbid); quinidine (Quinidex); quinine; ranitidine (Zantac); triamterene (Dyazide, Maxzide, others); or trimethoprim (Proloprim, Trimpex). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
• tell your doctor if you have or have ever had any medical condition, especially those mentioned in the IMPORTANT WARNING section .
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking metformin, call your doctor.
• if you are using the extended release tablets, you should know that sometimes the tablet shell may appear in your stool. If this occurs, it is not harmful and will not affect the way the medication works.
• tell your doctor if you eat less or exercise more than usual. This can affect your blood sugar. Your doctor will give you instructions if this happens.

What special dietary instructions should I follow?
Be sure to follow all exercise and dietary recommendations made by your doctor or dietitian. It is important to eat a healthful diet.

What should I do if I forget a dose?
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
 
What side effects can this medication cause?
Metformin is used to control the amount of sugar in your blood. You should know the symptoms of low and high blood sugar and what to do if you have them.
If you have any of these symptoms, eat or drink a food or beverage with sugar in it, such as hard candy or fruit juice, and call your doctor immediately; symptoms of low blood sugar (hypoglycemia) include:
• shakiness
• dizziness
• rapid heartbeat
• sweating
• confusion
• blurred vision
• headache
• numbness or tingling of the mouth
• weakness
• fatigue
• pale color
• sudden hunger
If you have any of these symptoms, call your doctor immediately; symptoms of high blood sugar (hyperglycemia) include:
• thirst
• dry mouth
• tiredness
• flushing
• dry skin
• frequent urination
• loss of appetite
• trouble breathing
Metformin may cause side effects. Tell your doctor if any of these symptoms are severe, do not go away, go away and come back, or do not begin for some time after you begin taking metformin:
• diarrhea
• upset stomach
• vomiting
• bloating
• stomach pain
• gas
• constipation
• unpleasant metallic taste in mouth
• heartburn
• headache
• sneezing
• cough
• runny nose
• sweating
• flushing of the skin
• nail changes
• muscle pain
Some side effects can be serious. The following symptoms are uncommon, but if you experience any of them or those listed in the IMPORTANT WARNING section, call your doctor immediately:
• chest pain
• rash.
Some female laboratory animals given high doses of metformin developed non-cancerous polyps (abnormal growths of tissue) in the uterus (womb). It is not known if metformin increases the risk of polyps in humans. Talk to your doctor about the risks of taking this medication.
Metformin may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.