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Accidentally Took 3000 mg Metformin: What to Do Now?

As a person related to the medical arena, I often get different questions related to health and medicine. But the question that I face the most is, “What to do when you accidentally take large amounts of your prescribed meds?”.

Overdosing on its own is very dangerous. However, overdosing with Metformin is uncommon. But, it can have serious consequences.

The U.S poison control center conducted a study. It stated that 4072 out of 11 million exposures are related to Metformin. That’s an average of one in 2500 exposures. Here is what you need to do if you accidentally took 3000 mg Metformin.

Table of Content

Metformin Use and Its Normal Doses

Metformin is mainly used to control blood sugar levels in the case of type 2 diabetes. You can also use it to maintain reproductive problems like PolyCystic Ovary Syndrome (PCOS).

Metformin is available in tablet form and solution form. Both of these forms are taken orally. We are going to talk about Metformin overdose and its side effects. But before that, let us have an idea about the normal doses.

accidentally took 3000 mg metformin

For adults aged 18 to 79 years, the dosage starts from 500mg twice daily or 850mg once daily. The doctor might gradually increase the dosage by 50mg per week or by 850mg every two weeks. The maximum dose is 2550mg per day. Not more than that.

For extended-release tablets, the starting dose is 500mg. The maximum dose is 2000mg per day. Adults above 80 years should not be prescribed Metformin without prior testing.

Metformin is only excreted through the kidney. The presence of prior kidney problems might lead to the accumulation of Metformin. Leading to a cumulative effect.

So, it’s apparent that accidentally taking 3000 mg Metformin is way above the normal dosage. If not taken care of properly, then it might have adverse effects on the body.

Accidentally Took 3000 mg Metformin: What’s Next?

Metformin overdose causes a whole lot of problems. But one of the most common and dangerous effects of Metformin overdose is lactic acidosis. It can also cause severe diarrhea and stomach pain. Body temperature may drop to cause Hypothermia.

It can also cause bradyarrhythmia. Since Metformin reduces plasma glucose level along with glucose production level, excessive intake can cause hypoglycemia.

Metformin overdose can affect the body in different ways. Let us explain some of the effects down below:

Lactic Acidosis

The most likely result of Metformin overdose is lactic acidosis. Lactic acidosis is a type of metabolic acidosis. This causes the blood pH to drop below 7.35. There is the presence of serum lactate of more than 2mmol per liter.

This exceeds the normal range of 0.5 to 2.2 mmol per liter for venous blood. For arterial blood, the normal range is 0.5 to 1.6 mmol per liter. Lactic acidosis may occur when someone has a contradictory condition such as renal insufficiency. We’ll get to the contradictions in another section.

The minimum lethal dose of Metformin for the development of lactic acidosis was recorded in a 42-year-old. The blood Metformin level was 188 µg per ml. Metformin causes lactic acidosis mainly by inhibiting gluconeogenesis.

It blocks the pyruvate carboxylase enzyme, which is needed to produce oxaloacetate. This enzyme is used for the first step of gluconeogenesis. This blockage of enzymes causes the formation of excessive amounts of lactic acid.

Metformin Toxicity

Metformin toxicity is one of the most adverse and dangerous conditions due to Metformin overdose. It is presented with a profound lactic acidosis. It progresses to the collapse of the cardiovascular system.

Toxicity has a high mortality rate. It can range from anything between 30% to 50%. The mortality rate can sometimes go up to 80%. But this isn’t very common. Along with lactic acidosis, there might be underlying causes like sepsis.

Metformin toxicity has more adverse effects in patients with susceptible conditions like renal failure, cardiac failure, and respiratory impairment. The only route of natural removal of Metformin is through excretion. Thus the proper renal function is necessary.

Severe lactic acidosis due to Metformin toxicity usually has non-specific symptoms. But in extreme cases may lead to shock, coma, and death. But it’s necessary to stay calm and contact your doctor immediately if there is a risk of toxicity.


Diarrhea occurring long after the start of Metformin therapy is quite common. It is also a very significant symptom of Metformin overdose. The most common side effects of Metformin are gastrointestinal side effects.

accidentally took 3000 mg metformin

One of the modes of action for Metformin is that it directly works on the gut. Thus it can lead to symptoms like nausea, vomiting, and diarrhea. This might cause frequent visits to the bathroom. Liquid explosive episodes might occur, which might lead to dehydration.

Vitamin B12 Deficiency

Around 30% of the people who use Metformin suffer from vitamin B12 deficiency. The effects are more prominent in the case of Metformin overdose. The users develop a reduced ability to absorb vitamin B12.

Vitamin B12 is absorbed in the gut. Since Metformin affects gut function, thus absorption is impaired. B12 deficiency can cause anemia, fatigue, drowsiness. It can also cause peripheral neuropathy, pins and needles, or numbness of hands and feet.

Doctors can treat vitamin B12 deficiency by taking supplements or injecting selected doses of B12. The injections are usually small monthly doses given in 3 months.


Nausea is another gastrointestinal side effect of Metformin overdose.  7% of Metformin users suffer from it when they accidentally took 3000 mg metformin.

The percentage may be higher if they do not take slow-release formulas. High amounts of Metformin in the blood affect gut motility. Thus it causes symptoms like nausea.

Metallic taste

Metformin overdose might cause a metallic or bitter taste on the tongue. Up to 3% of the patients complain about this effect. The taste should subside as the other symptoms of overdose are treated.


Metformin is a drug that doesn’t directly affect insulin concentration. However, Metformin overdose might cause hypoglycemia as it would drastically reduce gluconeogenesis. Metformin decreases basal glucose output. It also suppresses glycogenolysis in the liver.

As a result, it may cause reduced levels of blood sugar levels. If the glucose level is less than 3.3 mmol per liter, then it might lead to hypoglycemia.


The formation of hypothermia due to Metformin overdose is mainly related to hypoglycemia.  As explained by the Haematologica journal, hypoglycemia causes peripheral vasodilation. It also causes sweating and inhibits shivering. All of this, in the end, causes the body temperature to drop, causing hypothermia.


Metformin effects modulate the cardiovascular response to the intraduodenal glucose released by type 2 diabetic patients. After meals, the postprandial blood pressure may decrease, causing hypotension.

The diastolic and systolic pressure is decreased due to Metformin overdose. The heart rate, on the other hand, increases above normal.

Other effects of Metformin overdose

Besides the major effects mentioned above, Metformin overdose has other effects as well. They are mentioned as follows:

  • Vomiting
  • Epigastric pain or pain in the stomach
  • Excessive thirst
  • Loss of appetite
  • Tiredness or weakness
  • Trouble breathing

The most adverse effects may lead to renal failure, cardiac arrest, and coma. So, even if you face minor symptoms, it is advisable to visit your doctor immediately.

Risk factors of Metformin intake

Metformin usually isn’t administered to patients with kidney problems as it is the only mode of release from the body. Renal failure or impairment may lead to the accumulation of Metformin. This ultimately leads to lactic acidosis.

Patients with cardiac problems also need to be careful as Metformin has hypotensive and cardiac effects. So, if you have underlying conditions, then you should be careful about your Metformin administration.

If you accidentally take a double dose or 3000 mg of Metformin, you should immediately get checked.

Steps to be Taken for Metformin Overdose

If you accidentally took 3000 mg Metformin, then you should look at first monitor your symptoms. The intensity of the symptoms varies from person to person. In the meanwhile, you should avoid taking the next dose to balance out the Metformin.

 If you notice any of the symptoms related to Lactic acidosis, you should visit your doctor. You should keep measuring your blood sugar level to monitor its concentration.

If you are feeling hypoglycemic, you can take a meal rich in carbs or a small amount of sugar to relieve the symptoms. It would help if you always looked out for adverse symptoms.

In serious conditions, hemodialysis may be necessary. As Metformin is a dialyzable drug, you can remove it from the bloodstream through dialysis.

How to Prevent Accidental Overdosing?

You can use pill minders if you tend to overdose or miss your pills accidentally. The pill minders are small boxes with individual sections for storing pills. They come in all shapes and sizes.

On the other hand, you can take supplements to keep your blood sugar under control. However, you should always consult your doctor first to accommodate the supplements with your other meds.


Can I take 3000 mg of Metformin a day?

The usual maximum dosage for Metformin is 2000mg per day for extended-release tablets and 2500mg per day for standard-release tablets. However, there are 3000mg standard release tablets available, usually taken in rare cases.

So it is advised to take Metformin within the required range to avoid overdosing.

How much Metformin is lethal?

Taking 35 grams of Metformin has proven to be lethal. Lethal doses of Metformin may lead to lactic acidosis, renal and heart failure, coma, and ultimately death.

How much Metformin can I take in a day?

The maximum dose for Metformin is 2000mg per day. Your doctor will advise you how much is necessary for you and how to take it.

Final Thoughts

Metformin is one of the widely used drugs to control blood glucose for type 2 diabetic patients. It doesn’t play many roles in insulin concentration. But, it does affect the production and storage of glucose.

If you accidentally took 3000 mg Metformin, then you should stay calm and monitor symptoms. You should check your blood sugar levels. You can visit your doctor for further advice.

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