metformin side effects metformin side effects

Metformin Side Effects: Top 6 Important Side Effects

This post includes a guide on metformin side effects; the medication used to treat diabetes. 

Being a millennial may have seemed like the coolest thing ever about 20-25 years ago. But as we progress into what we seem to think is the peak of humankind as a civilization, the incredibly high levels of stress, anxiety, and fast-paced ways of our lives add to multiple diseases and disorders.

Especially with the advent of fast-food rich in unnecessary fats accompanied by extremely sugary drinks, smoking to manage said stress, and increased alcohol consumption, especially in women during pregnancy, lead to a seemingly common disease, diabetes mellitus. Studies have gone so far as to say diabetes mellitus is the non-communicable pandemic of the 21st Century.

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So what is diabetes?

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Diabetes is a medical condition caused due to abnormal/insufficient synthesis and storage of glucose in the body. It is again due to the improper functioning of a gland called the pancreas


. The pancreas is a tiny leaf-shaped gland under the stomach that produces insulin. It is responsible for controlling and regulating the blood sugar levels in the body.

All the hormones in the body are classified into hyperglycemia and hypoglycemic hormones. Hyperglycemia hormones


are the stress hormones such as cortisol. At the same time, norepinephrine and insulin are hypoglycemic hormones.

What is insulin?

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Insulin is a hormone that plays an essential part in carbohydrate breakdown in our body. It’s known as an endocrine hormone, which means it’s directly secreted into the blood to control blood levels of glucose. When it isn’t produced enough or isn’t produced the right way, there is a reduced breakdown of carbohydrates, which causes an increase in the levels of glucose in the blood.

When the breakdown doesn’t occur properly, the storage and utilization don’t normally happen as well. The liver is the storage store of glucagon, which is a modified form of glucose.

All you need to know about blood glucose/ blood sugar is that you must never have high blood sugar- called hyperglycemia. Neither should it go below the normal levels and cause low blood sugar levels and cause hypoglycemia.


It is excessive levels of sugar in the body before a meal or after.  The values may fluctuate between 130mg/dl to 200+mg/dl. This occurs when there is an insufficient amount of insulin or when there is abnormal insulin production. It causes long-term side effects such as the risk of lactic acidosis, diabetic retinopathy, diabetic peripheral neuropathy, embolism in the lung, brain, and heart.


It is abnormally low levels of sugar, below 70mg/dl. It needs immediate attention, as this is a very serious condition. When left untreated, the patient may lapse into a coma or may end up brain dead. It’s important to educate the patient regarding the symptoms and treatment of the condition.

Are there different types of diabetes?

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Yes. The American diabetes association classifies diabetes mellitus as a disease with three major manifestations: type 1 or insulin-dependent diabetes mellitus, type 2 or insulin-independent diabetes mellitus, and gestational diabetes mellitus.

Type 1 Diabetes

The first one, type 1 diabetes, presents itself early on, as young as 5-10 years old. It occurs due to improper/abnormal synthesis of the insulin hormone. The cause of type 1 diabetes may be due to genetic factors, or in most cases, it is idiopathic in onset.

Treatment for this type of diabetes is insulin therapy. The patient may be prescribed a combination of long-acting insulin and rapid-acting insulin to be taken immediately after a meal.

Type 2 diabetes

The second type, type 2 diabetes, is currently the most prevalent type of diabetes. It occurs in middle age groups of people. It is commonly due to reduced insulin hormone production.

The treatment is usually a choice of oral antidiabetic drugs such as metformin and glimepiride. The patient should take a couple of doses of these drugs per day to maintain blood glucose levels at the optimum.

Gestational diabetes

The third type, gestational diabetes, is essentially caused due to pregnancy. It occurs for the duration of a woman’s pregnancy and consequently resolves on its own.

It happens due to the increase in hormones that help maintain the pregnancy. Treatment consists of insulin therapy and, in some cases, insulin therapy with oral antidiabetic drugs that are safe in pregnancy.

What type of diabetes am I at a high risk of getting?

Since the second type of diabetes, or insulin-independent diabetes, is the most prevalent, it only fits we discuss the details of this disease, its management, and associated complications. Please ensure to take trustworthy health information from a qualified health professional and settle for nothing less.

Type 2 diabetes presents with different symptoms, such as unexplained weight loss or weight gain, excessive hunger or decreased appetite, excessive thirst, blurring of vision, lactic acidosis ( accumulation of lactic acid), and poor wound healing process.

In the long run, diabetes may present with side effects of peripheral neuropathy, or loss of sensation in legs, diabetic retinopathy or loss of vision, diabetic cataracts, thrombotic disease of the brain, lung, and kidney.

Do I have diabetes?

Call your doctor or health care provider immediately if you witness any of these symptoms because if you don’t reach out to health professionals following the signs, there will be diabetes-related complications.

Complications include lactic acidosis (high levels of lactic acid, a byproduct of regular body functioning), diabetic ketoacidosis, liver disease, kidney disease or kidney problems, increased risk of brain damage, lung damage, and heart disease.

Prescribed Medication

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Your doctor, upon proper investigations, will come up with a regular dosing schedule of drugs.


It is one of the most commonly prescribed diabetes medications. It is from a class of drugs called biguanides. It is a drug that has been approved by the U.S Food & Drug Administration as a medication to treat diabetes. 

How does metformin work?

Metformin works in multiple ways, such as;

1. Increasing the tissue sensitivity to whatever little insulin the pancreas produces.

2. It also reduces gluconeogenesis, a mechanism by which the liver produces glucose from non-carbohydrate sources such as proteins and fats. It helps in blood sugar control and prevents high blood sugar caused by gluconeogenesis.

3. It stimulates the breakdown of glucose in tissues called glycolysis.

4. It reduces appetite.

5. Reduces the glucagon levels in plasma, which is a storage form of glucose.

Are there different types of metformin?

Yes, metformin is of different types,

1. Rapid release metformin: which acts quickly and is usually prescribed twice a day. 

2. Extended-release metformin: this acts for a longer duration and is prescribed once a day. 

The most commonly prescribed type is extended-release tablets. In the most simple term, it means that the drug’s action is dragged out for a longer period to ensure maintenance of blood sugar levels so that the patient doesn’t have to pop a pill every few hours. It also cuts costs for the patient in terms of securing medication. 

Extended-release metformin is usually prescribed once a day. Your doctor may start with a low dose and gradually increase your dosage based on how your body responds to the medication.

Taking metformin; are there any specific points I must remember while I take metformin?

The dosing of metformin is 500mg oral dosing twice a day. It is well absorbed in the gut, and the duration of action is between 8-12 hours, depending on whether it is extended-release metformin or regular metformin.

Metformin is available as a generic drug form and brand names such as Fortamet and Glumetza.

Your health care team may prescribe what is best for you based on your history with medications. It’s important to take your medication regularly and on time.

What do I do if I miss a dose of metformin?

If you realize you’ve missed a dose of taking metformin, take medicine if it has been less than a couple of hours late. If you know you missed an amount close to the next dose, then continue with the next dose and do not take a double dose.

Taking a double dose, even if by mistake, causes metformin side effects. 

Is there a risk of overdosing on metformin?

Too much metformin that is a dose of over 2000mg per day is dangerous. It may lead to breathing troubles, dizziness, blurring of vision, low blood sugar, weakness, lactic acidosis ( high levels of lactic acid), stomach pain, and others. 

To control these metformin side effects, your doctor may put you on observation for a couple of days; once your condition gets stabilized from the metformin side effects, your doctor will provide medical advice regarding the dosing accordingly.

Metformin Side Effects: Specifically the Extended-Release Tablet, May Include:

1. Stomach pain

It is one of the more common metformin side effects caused due to acid imbalance in the stomach.

2. Severe diarrhea

Severe diarrhea is another one of the metformin side effects caused due to improper functioning of the gut wall.

3. Kidney problems

Kidney problems are one of the more serious metformin side effects. It doesn’t directly cause kidney damage, but a perceived risk of lactic acidosis or lactic acid accumulation causes kidney damage. Lactic acid is a byproduct of regular body metabolism, which is essentially harmless unless it gets accumulated.

Our body tries to maintain a neutral pH which has a feature called buffering. It means the pH of the blood will not change unless a very high amount of acid is released into the blood. Lactic acid does just that leading to conditions called respiratory acidosis, acidic urine, and so on. 

4. Metallic aftertaste

A metallic aftertaste in the mouth is one of the most specific metformin side effects. 

5. Severe nausea

Severe nausea and vomiting are the most common metformin side effects.

6. Metformin cannot be used in patients with renal disease

It can not be used in patients with liver disease and patients who are using calcium channel blockers. It causes trouble breathing or may cause rapid breathing, severe liver problems, breakdown of your red blood cells, lactic acidosis (lactic acid is a byproduct of body functions which, when accumulated, causes pH imbalances). 

If you face any metformin side effects mentioned above, kindly call your doctor immediately or inform your nearest healthcare professional.

Rare Metformin Side Effects

In rare cases, people consuming metformin may face heartburn, headaches, a bad taste in their mouth, or upper respiratory infection. People may also face flu-like symptoms, nail problems, rashes, flushing, heart palpitations, and sweating. 

Behavioral changes, lack or loss of strength, and drowsiness may also be rare metformin side effects. Such metformin side effects need immediate medical attention. 

Advantages of extended-release metformin:

1. It mimics insulin-like activities.

2. It does not cause hypoglycemia.

3. It reduces weight, which is especially helpful in obese patients.

4. It has a lower incidence and risk of lactic acidosis compared to other medications.

Is metformin the only medication available for diabetes?

Other diabetes medications include insulin secretagogues such as Glimepiride, DPP-4 inhibitors such as Sitagliptin, SGLT-2 Inhibitors such as dapagliflozin. Although metformin side effects can be controlled by altering the type of metformin prescribed.

Suppose you have excessive difficulty with metformin side effects that do not resolve on dose correction. In that case, you may be prescribed metformin with other medicines such as PPIs to help with the other symptoms or with other drugs specific to diabetes glimepiride.

Management of metformin side effects: can I prevent metformin side effects?

You can prevent metformin side effects by taking the prescribed dosage at the appropriate time. Informing your healthcare providers immediately if you experience any side effects is key to avoid any life-threatening complications.

Metformin side effects can go away at their natural pace; however, there are a few ways in which you can ease the metformin side effects: 

1. Start with a low dose

You can ask to start with a low dose to prevent metformin side effects. It allows your body enough time to adjust to the medicine. 

2. Try not to take metformin empty stomach: 

You can take metformin on an empty stomach, but having the medicine with food will make it easier to handle. When you take medicine with food, it reduces the chances of stomach irritation as well. 

3. Enquire about the extended-release form: 

What are the lifestyle modifications I must keep in mind?

Along with medications, your doctor may prescribe some lifestyle modifications.

They may include;

1. Diet control:

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You must ensure your diet is rich in fiber-rich food. You must take strict measures to control sugar and carbohydrate intake. Containing carbohydrates helps control glucose production.

2. Regular exercising:

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Irrespective of whether the disease made you lose or gain weight, you must ensure you exercise regularly. It provides proper blood supply to your limbs and maintaining good respiratory functioning. Obese patients will have to undergo weight loss training for better compliance and to prevent side effects.

3. Regular checkups:

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Ensure that you regularly check your blood glucose levels and other lipid levels in the blood to prevent heart and liver complications.

4. Manage stress:

Stress releases a hormone called cortisol. Cortisol increases blood glucose levels, hence manage your stress. Meditate, learn calming methods, and anger management if necessary.

5. How much alcohol can I drink?

Drinking alcohol is not ideal when managing diabetes. It is because alcohol causes extreme reactions.
Various sugary alcohols such as wine can increase your blood glucose levels, and binge drinking hard liquors such as whiskey lead to dangerously low levels of sugar that can cause brain damage, coma, and in severe cases, death. Hence preferably avoid alcohol altogether.

6. Stop smoking:

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Smoking causes a wide myriad of diseases such as cataracts, lung damage, liver damage, kidney diseases, heart diseases, and the list is endless. When combined with uncontrolled diabetes, the results are fatal.

7. Contraception:

Women with diabetes may have to discuss the use of oral contraceptives with their health care provider, although the advantages outweigh the associated risks. Mechanical contraceptives cause a much lesser threat to advantage ratio.

8. Polycystic ovary syndrome:

Women with PCOS are usually resistant to insulin and hence discuss the disease management with their doctors. It may be challenging to manage both the diseases simultaneously, but with weight loss, a controlled diet, stress management, and regular exercising, both PCOS and diabetes may be controlled.

9. Wear compression stockings:

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Due to diabetes, there is an increased ability of the blood to form clots. It means that the lesser perfused areas of the body, such as legs, may end up with lumps, reduced sensation, and in severe cases, gangrene and necrosis.

To prevent this, it’s important to wear compression stockings that ensure proper blood supply and avoids clot formation.

10. Prevent injuries:

Injuries take longer to heal, and diabetes is an immunocompromised state, which means increased difficulty in treating infections, even with modern antibiotics.

So diabetic patients need to try and prevent injuries. Even if injured, they must immediately reach out to a healthcare professional to get it sterilized and dressed properly.

Final Thoughts: Can I Prevent Diabetes?

Yes. Multiple factors may cause diabetes, such as: 

1. Modifiable risk factors: these factors may be controlled. They include maintaining an ideal body weight, no smoking, no alcohol, reducing fatty foods, red meat, and foods with high sugar content.

2. Non-modifiable risk factors: include genetic predisposition( if it runs in the family and first-degree relatives, the incidence is higher) idiopathic causes or causes of unknown origin. 

You are now equipped with all the essential knowledge regarding diabetes as a disease, ways to prevent any metformin side effects, and their specific management. I hope you found this article useful. 

To know more about metformin’s side effects, you may check out this website. 

  1. Leung, Po Sing, and Po Sing Leung. “Overview of the pancreas.” The Renin-Angiotensin System: Current Research Progress in The Pancreas: The RAS in the Pancreas (2010): 3-12. ↩︎
  2. Sacca, Luigi, ROSA HENDLER, and ROBERT S. SHERWIN. “Hyperglycemia inhibits glucose production in man independent of changes in glucoregulatory hormones.” The Journal of Clinical Endocrinology & Metabolism 47.5 (1978): 1160-1163. ↩︎

Last Updated on by Sanjana


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