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 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.

Special precautions

Before taking metformin,

• Tell your doctor and pharmacist if you are allergic to metformin or any other medicines.

• Tell your doctor and pharmacist if you are taking vitamins, nutritional supplements, and herbal products.

• Tell your doctor if you have or have ever had any medical condition.

• 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.

Side effects

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:

• 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:

• chest pain

• rash

Do not let anyone else take your medicines.