Metformin

Metformin is a prescription medication used to treat type 2 diabetes. Metformin belongs to a group of drugs called biguanides, which work by helping your body respond better to the insulin it makes naturally, decreasing the amount of sugar your liver makes, and decreasing the amount of sugar your intestines absorb.

This medication comes in tablet, extended-release tablet, and liquid forms. It is taken up to 3 times daily, depending on which form you are taking. Swallow extended-release tablets whole.

Common side effects of metformin include diarrhea, nausea, and upset stomach.

Metformin is a prescription medication used to treat type 2 diabetes.

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

Metformin may be found in some form under the following brand names:

• Actoplus Met

• Avandamet

• Fortamet

• Glucophage

• Glucovance

• Glumetza

• Invokamet

• Janumet

• Jentadueto

• Kazano

• Kombiglyze XR

• Metaglip

• PrandiMet

• Riomet

Serious side effects have been reported including:

Lactic Acidosis. In rare cases, metformin can cause a serious side effect called lactic acidosis. This is caused by a buildup of lactic acid in your blood. This build-up can cause serious damage. Lactic acidosis caused by metformin is rare and has occurred mostly in people whose kidneys were not working normally. Lactic acidosis has been reported in about one in 33,000 patients taking metformin over the course of a year. Although rare, if lactic acidosis does occur, it can be fatal in up to half the people who develop it.

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take:

• beta-blockers
• cough and cold products containing decongestants
• calcium channel blockers
• cimetidine (Tagamet)
• corticosteroids
• digoxin (Lanoxin)
• diuretics such as furosemide (Lasix)
• estrogens
• insulins or other medicines for diabetes
• isoniazid (INH, Nydrazid)
• morphine
• niacin (nicotinic acid, Niaspan)
• nifedipine
• oral contraceptives
• oral steroids
• phenothiazines such as promethazine (Phenergan)
• phenytoin (Dilantin)
• procainamide
• quinidine
• quinine
• ranitidine
• thyroid medicines such as levothyroxine (Levothroid, Levoxyl, Synthroid, Tirosint)
• triamterene
• trimethoprim
• vancomycin

This is not a complete list of metformin drug interactions. Ask your doctor or pharmacist for more information.

A small number of people who have taken metformin have developed a serious condition called lactic acidosis. Lactic acidosis is caused by a buildup of lactic acid in the blood. This happens more often in people with kidney problems. Most people with kidney problems should not take metformin. See "Side Effects".

Some conditions increase your chance of getting lactic acidosis, or cause other problems if you take metformin. Most of the conditions listed below can increase your chance of getting lactic acidosis.

Do not take metformin if you:

• have kidney problems
• have liver problems
• have heart failure that is treated with medicines, such as Lanoxin (digoxin) or Lasix (furosemide)
• drink a lot of alcohol. This means you binge drink for short periods or drink all the time.
• are seriously dehydrated (have lost a lot of water from your body)
• are going to have an x-ray procedure with injection of dyes (contrast agents)
• are going to have surgery
• develop a serious condition, such as heart attack, severe infection, or a stroke
• are 80 years or older and you have NOT had your kidney function tested

Do not drink a lot of alcohol drinks while taking this medication. This means you should not binge drink for short periods, and you should not drink a lot of alcohol on a regular basis. Alcohol can increase the chance of getting lactic acidosis.

Follow dietary (food) recommendations made by your doctor and dietitian which should include a healthy diet. Skipping meals should be avoided as this can cause problems maintaining blood sugar control. There are no specific foods to avoid while using Metformin.

Before receiving metformin, tell your doctor if you:

• have kidney problems
• have liver problems
• have heart failure that is treated with medicines, such as Lanoxin (digoxin) or Lasix (furosemide)
• drink a lot of alcohol. This means you binge drink for short periods or drink all the time.
• are seriously dehydrated (have lost a lot of water from your body)
• are going to have an x-ray procedure with injection of dyes (contrast agents)
• are going to have surgery
• develop a serious condition, such as heart attack, severe infection, or a stroke
• are 80 years or older and you have NOT had your kidney function tested
• are pregnant or breastfeeding

While taking metformin, tell your doctor if you

• have an illness that causes severe vomiting, diarrhea or fever, or if you drink a much lower amount of liquid than normal. These conditions can lead to severe dehydration (loss of water in your body). You may need to stop taking metformin for a short time.
• plan to have surgery or an x-ray procedure with injection of dye (contrast agent). You may need to stop taking metformin hydrochloride tablets for a short time.
• start to take other medicines or change how you take a medicine. Metformin can affect how well other drugs work, and some drugs can affect how well metformin works. Some medicines may cause high blood sugar.

Tell your doctor if you are pregnant or plan to become pregnant. It is not known if Metformin will harm your unborn baby.

Tell your doctor if you are breastfeeding or plan to breastfeed. It is not known if metformin is excreted in human breastmilk or if it will harm your nursing baby.

Metformin is taken by mouth and is available as a tablet, an extended-release tablet, and as a liquid. Depending on which product you are taking, you will either take it once daily or up to three times daily. Metformin should be taken at the same time(s) each day. The extended-release tablets should not be chewed, split, or crushed. Swallow metformin extended-release tablets whole.

Your doctor will tell you how much medicine to take and when to take it. You will probably start out with a low dose of the medicine. Your doctor may slowly increase your dose until your blood sugar is better controlled. You should take metformin with meals.

Your doctor may have you take other medicines along with metformin to control your blood sugar. These medicines may include insulin shots. Taking metformin with insulin may help you better control your blood sugar while reducing the insulin dose.

Continue your exercise and diet program and test your blood sugar regularly while taking metformin.

Your doctor will monitor your diabetes and may perform blood tests on you from time to time to make sure your kidneys and your liver are functioning normally. There is no evidence that metformin causes harm to the liver or kidneys.

Take metformin exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

The recommended starting dose of metformin is 500 mg twice daily or 850 mg once a day (in people 17 and older), given with meals. The maximum recommended daily dose is 2000 mg in children (10 to 16 years of age) and 2550 mg in adults. The dosage should be increased slowly to avoid side effects.

For the extended release form, metformin ER, the starting dose is metformin ER 500 mg once daily, and the maximum dosing is metformin ER 2000 mg once daily (or metformin ER 1000 mg twice daily).

For the metformin oral solution, the usual maximum adult dose is 25 ml each day (equivalent to 2500 mg).

The maximum total daily dose of metformin for people taking insulin is 2500 mg. For the extended release form, metformin ER, 2000 mg is the maximum total daily dose with insulin.

If you take too much Metformin, call your local Poison Control Center or seek emergency medical attention right away.

Store metformin at room temperature away from excess light and humidity.

Keep this and all medicines out of the reach of children.

WARNINGS