What are Glucophage (metformin) side effects?

Glucophage causes changes in your blood sugar levels. You should be aware of the signs and symptoms of high and low blood sugar and know what to do if you develop these symptoms. The most common side effects of Glucophage include:

• Diarrhea
• Stomachache
• Bloating
• Gas
• Indigestion
• Heartburn
• Constipation
• Headache
• Metallic taste in the mouth
• Skin flushing
• Nail changes
• Muscle aches

Please tell your doctor if these Glucophage side effects are severe, do not go away, go away but come back again, or develop some time after you start taking the medication. 

Some of the side effects of Glucophage are more serious. You should contact your doctor without delay or get emergency treatment for the following side effects:

• Chest pain
• Rash
• Difficulty breathing
• Irregular heart rate
• Dizziness

The above list may not include all the potential side effects of Glucophage. Talk to your doctor if you have severe side effects or if the side effects do not improve over time. You can also report unusual Glucophage side effects to the Food and Drug Administration at 1-800-FDA-1088.

Glucophage overdose: Under certain conditions, an overdose of Glucophage can cause a serious, potentially life-threatening condition called lactic acidosis. Symptoms of Glucophage overdose can include symptoms of hypoglycemia (low blood glucose levels), weakness, extreme tiredness, nausea, vomiting, stomach pain, decreased appetite, shortness of breath, rapid and deep breathing, lightheadedness, dizziness, abnormally slow or fast heartbeat, feeling cold, flushing of the skin, and muscle pain. If you experience any of these symptoms, stop taking Glucophage and call your doctor immediately. NOTE: Glucophage is a prescription medicine to be used only by you - never share your medication with others or use someone else’s Glucophage.

Source: FDA