Question

Metformin

What are the side effects of metformin?

A Answers (4)

  • AStacy Wiegman, PharmD, Pharmacy, answered
    The most common and less serious side effects of metformin are bloating, gas, stomach pain, weakness, diarrhea, constipation, heartburn, sneezing, headaches, cough, flushing of the skin, vomiting, runny nose, nausea and muscle pain. If you have chest pain or a rash, seek immediate medical help. Also call for emergency help if you have any symptoms of lactic acidosis: weakness, cold feeling, increasing sleepiness, slow heart rate, shortness of breath, muscle pain, stomach pain, light-headedness, and fainting. Hives, swelling of your face, lips, tongue or throat, and difficulty breathing could be a sign of an allergic reaction. Call your doctor if you begin gaining weight, notice swelling or develop flu-like symptoms. Metformin may cause hypoglycemia, which is low blood sugar. Symptoms for hypoglycemia are dizziness, shakiness, irritability, nervousness, changes in mood or behavior, headaches, weakness, numbness or tingling around your mouth, hunger, pale skin, and clumsy movements. If you do not get treated for hypoglycemia, it can become more severe and graduate into confusion, followed by seizures and loss of consciousness.
    You can also develop hyperglycemia, which is high blood sugar. Symptoms are frequent urination, extreme hunger, thirst, blurred vision and weakness. If not treated, it can develop into a more serious life-threatening diabetic ketoacidosis. Symptoms are nausea, vomiting, dry mouth, fruity smelling breath and lapsing in unconsciousness. Because metformin is used in combination drugs, some of those other active ingredients may also have side effects.

  • AAudrey K. Chun, MD, Internal Medicine, answered on behalf of The Mount Sinai Health System
    Metformin (prescribed to treat type 2 diabetes) can cause excessive gas and bloating, heartburn, headaches, a cough, muscle pain and a metallic taste in the mouth, but these side effects typically ease after a few weeks. Very rarely, metformin may cause a serious condition called lactic acidosis. Key signs include weakness, trouble breathing, abnormal heartbeat, unusual muscle pain, stomach discomfort, lightheadedness and feeling cold. You're more at risk if you have reduced kidney function, worsening congestive heart failure or are dehydrated.
  • Metformin is prescribed for people with type 2 diabetes. Like any medication, it carries the risk of side effects. The most common side effects from metformin include nausea, diarrhea, gas and upset stomach. These are most likely when you first start taking it and usually go away on their own. Until they do, you should try to take your metformin with a meal. You can also try reducing the amount you take for a few days and gradually increasing it until you’ve reached the amount your doctor has prescribed for you.

    Lactic acidosis is a very rare -- but very serious -- side effect. It happens most often in people with liver, kidney or respiratory diseases. Call your doctor right away if you have any of these symptoms of lactic acidosis: weakness, stomach pain or discomfort, fast and shallow breathing, sleepiness and muscle cramping.

    Although metformin doesn’t cause hypoglycemia by itself, if combined with other medications, vigorous exercise or too little food, it can make your blood glucose drop too low.

    Since low blood glucose can be dangerous, make sure that you and your family know the symptoms. These include feeling shaky, sweaty, hungry, and irritable. If you have these symptoms, take some quick-acting sugar. Good sources are three or four glucose tablets, a half-cup of fruit juice or regular soda, or a tablespoon of honey or sugar.

    You should call your doctor if you have side effects that don’t go away or if you have any symptoms of lactic acidosis.
  • AMediGuard answered
    Diarrhea, abdominal cramps, and nausea and vomiting are common side effects of metformin. When starting metformin, using a lower starting dose and gradually increasing the dosage may help to minimize these gastrointestinal symptoms. Usually these side effects will go away as your body becomes used to metformin. Taking metformin with food may also help with these gastrointestinal symptoms.
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What should I know about metformin before taking it?