Side Effects of Metformin

Metformin is a prescription substance abuse to treat type 2 diabetes. It comes from a class of medications called biguanides. People with type 2 diabetes have blood sugar (glucose) levels that increase higher than normal. Metformin doesn’t cure diabetes. Instead, it assists reduce your blood sugar levels to a safe variety.

Metformin has to be taken long-term. This may make you question what side effects it can cause. Metformin can cause moderate and serious side effects, which are the same in men and women. Here’s what you need to understand about these side effects when you need to call your doctor.

More Common

Metformin causes some common side effects. These can occur when you first begin taking metformin, however normally go away in time. Inform your doctor if any of these symptoms are severe or cause a problem for you.

The more common side effects of metformin consist of:

  • heartburn
  • nausea or vomiting
  • bloating and gas
  • diarrhea or constipation
  • weight-loss
  • headache
  • stomach pain
  • undesirable metal taste in mouth


Lactic acidosis

The most serious side effect metformin can cause is lactic acidosis. In truth, metformin has a boxed caution about this risk. A boxed caution is the most severe warning from the Food and Drug Administration (FDA).

Lactic acidosis is an uncommon however severe issue that can occur due to a buildup of metformin in your body. It’s a medical emergency that must be dealt with right away in the healthcare facility. See Precautions for aspects that raise your risk of lactic acidosis.

Call your doctor right away if you have any of the following symptoms of lactic acidosis. If you have problem breathing, call 911 right now or go to the closest emergency room.

  • vomiting
  • extreme tiredness
  • problem breathing
  • lightheadedness
  • weakness
  • flushing (unexpected reddening and warmth in your skin)
  • feeling cold
  • decreased hunger
  • a fast or slow heart rate
  • dizziness
  • stomach pain with any of these other symptoms
  • nausea
  • muscle pain


Metformin can decrease the levels of vitamin B-12 in your body. In uncommon cases, this can cause anemia (low levels of red cell). If you do not get much vitamin B-12 or calcium through your diet, you might be at greater risk of really low vitamin B-12 levels. Your vitamin B-12 levels can enhance if you stop taking metformin or take vitamin B-12 supplements. Do not stop taking metformin without speaking to your doctor, however.

The more typical symptoms of anemia consist of:

  • tiredness.
  • dizziness.
  • lightheadedness.

If you think you may have anemia, make an appointment with your doctor to inspect your red blood cell levels.


Alone, metformin does not cause hypoglycemia (low blood sugar). However, in rare cases, you might develop hypoglycemia if you combine metformin with:

  • a bad diet.
  • extreme alcohol intake.
  • strenuous workout.
  • other diabetes medications.

Call your doctor if you have any symptoms of hypoglycemia, which can consist of:

  • nausea.
  • stomach pain.
  • weak point.
  • lightheadedness.
  • vomiting.
  • unusually quick or sluggish heart beat.
  • dizziness.
  • fatigue.

Safety Measures

A number of aspects raise your risk of lactic acidosis while you take metformin. If any of these factors affect you, make certain to discuss them with your doctor prior to taking this drug.

Kidney issues

Your kidneys remove metformin from your body. If your kidneys don’t work well, you’ll have higher levels of metformin in your system. This raises your risk of lactic acidosis.

If you have mild or moderate kidney issues, your doctor might begin you at a lower dose of metformin. If you have severe kidney problems or are 80 years or older, metformin may not be right for you. Your doctor will likely test your kidney function prior to you start taking metformin and then again each year.

Heart issues

If you have severe heart failure or have recently had a cardiac arrest, you ought to not take metformin. Your heart might not send out enough blood to your kidneys. This would prevent your kidneys from removing metformin from your body in addition to they usually would, raising your risk of lactic acidosis.

Liver issues

You need to not take metformin if you have severe liver problems. Your liver clears lactic acid from your body. For that reason, severe liver issues could cause an accumulation of lactic acid. Lactic acid accumulation raises your risk of lactic acidosis. Metformin also raises your risk, so taking it if you have liver problems is dangerous.

Alcohol use

Drinking alcohol while taking metformin raises your risk of hypoglycemia. It likewise raises your risk of lactic acidosis. This is since it increases lactic acid levels in your body. strongly recommends completely stop drinking alcohol.

Surgical or radiologic procedures

If you prepare to have surgery or a radiology procedure that uses iodine contrast, you must stop taking metformin 48 hours before the procedure. These procedures can slow the removal of metformin from your body, raising your risk of lactic acidosis. You must resume taking metformin after the procedure just when your kidney function tests are normal.

Talk with your doctor

If your doctor has actually recommended metformin and you’re worried about its side effects, talk with your doctor. You might want to evaluate this short article with them. Make certain to ask any concerns you have, such as:.

  • What side effects should I keep an eye out for?
  • Am I at high risk of lactic acidosis?
  • Exists another medication I could take that might cause fewer side effects?

Your doctor can answer your questions and work with you to handle any side effects you may have.

Does metformin cause weight-loss?
Metformin can cause weight-loss with time when combined with diet and workout. However, metformin should not be used just for weight loss. It has the risk of major side effects as well as interactions with other medications. Also, metformin does not supply long-lasting weight reduction. After stopping taking metformin, people usually acquire back any weight they’ve lost from the drug.

What drugs interact with metformin?
Cationic drugs (e.g., amiloride, digoxin, morphine, procainamide, quinidine, quinine, ranitidine, triamterene, trimethoprim, or vancomycin) that are removed by renal tubular secretion in theory have the potential for interaction with metformin by contending for typical renal tubular transport systems.

When should you not take metformin?
Metformin ought to be taken with meals to assist reduce stomach or bowel side effects that might take place during the first few weeks of treatment. Swallow the extended-release tablet whole with a complete glass of water. Do not crush, break, or chew it.

What are the side effects of long term use of metformin?
Likewise, to help lessen your risk of severe diarrhea, your doctor will likely start you on a low dose of metformin and then increase it gradually.

  • heartburn.
  • stomach pain.
  • nausea or vomiting.
  • bloating.
  • gas.
  • diarrhea.
  • constipation.
  • weight-loss.

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