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Side effects of stopping metformin

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EffectsTaperingMissed dosesAlternativesSummary
Metformin may cause hyperglycemia symptoms like nausea, headaches, and diarrhea if you stop taking it abruptly without gradually reducing the dose. Consider talking with a healthcare professional before stopping or changing your metformin treatment.
Medically reviewed by Alexandra Perez, PharmD, MBA, BCGP
Written by Rashida Ruwa, RN
Updated on December 14, 2023

Metformin is a common prescription oral medication approved by the Food and Drug Administration (FDA) for type 2 diabetes. It belongs to the class of biguanide drugs. These work by decreasing the amount of glucose your liver produces and improving how your body uses insulin.

Metformin is available in the United States under various brand names, such as:

  • Glucophage
  • Riomet
  • Glumetza
  • Fortamet

Metformin is available in immediate and extended-release formulations. Doctors often combine it with other antidiabetic agents for more thorough treatment.

Healthcare professionals may also prescribe metformin off label for certain conditions, including:

  • prediabetes
  • polycystic ovary syndrome (PCOS) 
  • gestational diabetes
  • antipsychotic-induced weight gain

Need a refill for metformin (Glucophage)? You may be able to get an online prescription through Optum Perks in as little as 15 minutes with no video or appointment needed. Learn more here.

Symptoms related to discontinuing metformin

Woman feeling tired as a side effect of stopping metformin
Corinna Kern/Getty Images

The physical and psychological changes you experience when stopping a medication are known as withdrawal symptoms, not side effects.

Withdrawal symptoms are more common when discontinuing long-term medications or those that may have a higher risk of causing chemical dependence.

If you suddenly stop taking metformin, it may lead to high blood sugar (hyperglycemia) levels. Signs of high blood sugar may include:

  • dry mouth
  • headaches
  • frequent urination
  • increased thirst or hunger
  • fatigue or weakness
  • blurred vision
  • unexplained weight loss

Symptoms may vary in severity and depend on how else you manage your blood sugar besides metformin.

Other possible withdrawal symptoms of metformin may include:

  • abdominal discomfort like stomach cramps, bloating, or nausea
  • headaches
  • lightheadedness
  • tremors
  • fatigue and weakness

Before changing your treatment plan, it is important to talk with a healthcare professional to understand the potential effects of stopping metformin abruptly.

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Do you need to taper metformin?

Tapering is a gradual reduction of a medication’s dosage to minimize the risk of withdrawal symptoms or adverse effects. It allows your body to slowly adjust to the changes and, with metformin, helps maintain stable blood sugar levels.

Stopping metformin abruptly without tapering off may lead to more intense withdrawal symptoms.

As metformin affects how the body regulates glucose, a sudden decrease in medication may cause unstable blood sugar. As a result, the body may react severely.

You may experience some withdrawal symptoms during tapering. These may vary in intensity depending on various factors, such as:

  • the tapering plan
  • how long you have been taking metformin
  • individual differences in metabolism

It is advisable to work closely with a healthcare professional when tapering off metformin to minimize the risk of withdrawal symptoms and any possible complications, such as kidney disease.

What happens if you miss one dose of metformin?

Missing one dose of metformin doesn’t usually lead to withdrawal symptoms. However, it’s important to take your medication as prescribed to maintain stable blood sugar levels and manage your diabetes effectively.

If you accidentally miss a metformin dose, here’s what you can do:

  • Take the missed dose as soon as you remember. If it’s close to the time of your next scheduled dose, skip the missed dose and continue with your regular dosing schedule.
  • Do not double the next dose to make up for the missed one. Taking more than your prescribed dose could increase the risk of side effects and complications.

If you frequently forget to take your medication, consider using reminders or incorporating it into your daily routine to help you remember.

Alternatives to metformin

Common alternative medications to metformin include:

  • For type 2 diabetes: Sulfonylureas stimulate the pancreas to release more insulin, helping lower blood sugar levels. Examples include:
  • For PCOS: Birth control pills regulate menstrual cycles and reduce androgen levels in people with PCOS. Common types include:
  • For gestational diabetes: Insulin is the standard treatment for managing blood sugar levels during pregnancy when diet and exercise aren’t enough. Insulin has a long history of safe and effective use.
  • For the prevention or delay of type 2 diabetes in high risk individuals: Alpha-glucosidase inhibitors slow down the breakdown of carbohydrates in the intestine, which may help manage blood sugar levels after meals. Examples include:

It is important to note that the medications above have different mechanisms of action and may not be suitable for every person. 

As with any drug, it’s advisable to speak with a healthcare professional before starting or changing a dose. They may assess your medical history, consider potential drug interactions, and provide personalized recommendations based on your needs.

Download the free Optum Perks Discount Card to save up to 80% on some prescription medications.


Discontinuing metformin may lead to a temporary worsening of blood sugar management in people with diabetes. Some people may also experience withdrawal effects such as headaches and diarrhea.

It is important to speak with a healthcare professional before changing your medication regimen.

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