Tips for Avoiding Metformin Side Effects - GoodRx (2024)

Many people with Type 2 diabetes, as well as many individuals with prediabetes, take metformin to control their blood sugar. When taken as prescribed, the benefits of metformin typically outweigh its risks of side effects.

However, some side effects of metformin can be a hassle — especially when first starting the medication. Diarrhea, nausea, and passing gas are common to experience while taking metformin. But are there any tips for avoiding or relieving these side effects while your body adjusts to the medication?

Typical metformin side effects

Metformin can be a bit tough on the digestive tract, especially when first starting it. In one study, over half the people taking metformin experienced a gastrointestinal (GI) side effect — an issue with the stomach or digestive tract.

The most common metformin side effects include:

• Diarrhea

• Nausea

• Vomiting

• Gas

Researchers are still studying why these metformin side effects are so common. One potential explanation is that metformin can change your gut microbiome — a unique blend of bacteria, viruses, and fungi that help us digest food and stay healthy. If this delicate balance shifts, it could lead to tummy troubles like diarrhea and gas.

Lactic acidosis: A rare but serious side effect of metformin

Lactic acidosis is a very rare complication that could happen when taking metformin. Lactic acid is a substance our bodies use to create glucose (sugar). Metformin, in part, helps prevent the creation of glucose, so this can lead to a buildup of lactic acid in the blood.

Lactic acidosis is when lactic acid levels get too high — and it can be fatal if left untreated. This is a medical emergency that needs immediate hospital care. Symptoms of lactic acidosis include:

• Trouble breathing

• Tiredness

• Muscle aches

• Stomach pain

Lactic acidosis rarely happens unless a person has taken too much of metformin. Other conditions or situations that put you at a higher risk of experiencing lactic acidosis with metformin are:

• Advanced chronic kidney disease (stage 4 or 5)

• Liver disease

• Drinking excessive amounts of alcohol

• Unstable heart failure

• Age 65 or older

• Being dehydrated

• Taking certain medications that interact with metformin

  See Also

  Metformin (Oral Route) Side EffectsMetformin Side Effects: What's Normal? - K HealthWhat are the side effects of metformin?Metformin: Wie es wirkt, was Sie wissen müssen.

Your risk is also higher if you are very unwell and in the hospital with:

• Pneumonia

• Sepsis

• Another serious infection

It’s important to keep up to date with all blood work that your healthcare provider orders. This will help them monitor things like kidney and liver health, keeping your risk of lactic acidosis as low as possible.

Who shouldn’t take metformin?

Just as with any medication, metformin is not right for everyone. Due to their greater vulnerability to metformin side effects, the following people are usually not given metformin:

• Those with stage 4 or 5 kidney disease

• People with Type 1 diabetes

• Older adults with prediabetes

• People currently experiencing diabetic ketoacidosis

• People with certain liver problems

Your healthcare provider will be the one to ultimately decide if metformin is right for you. Make sure to bring up any concerns you have about taking this medication with your provider.

Metformin side effects in men

Common metformin side effects aren’t known to affect people differently based on sex or gender. However, there may be a concern of whether metformin could be linked to sexual side effects, such as erectile dysfunction (ED). A small study showed that men taking metformin had lower levels of testosterone — a hormone linked to male sexual health.

However, this study should be considered alongside other risk factors for ED. Type 2 diabetes is known to cause ED, especially if your blood sugar isn’t under control. If you have obesity or overweight, you are also at a higher risk of developing ED. If your ED symptoms began after starting metformin, it’s best to discuss it with your healthcare provider.

Metformin side effects in women

As just discussed, common metformin side effects should be the same regardless of gender. However, there is a condition under which women who menstruate may notice a different side effect than those who don’t.

Metformin is sometimes used as an off-label treatment for polycystic ovary syndrome (PCOS). Depending on what symptoms you’re experiencing and other medical conditions you have, metformin could be used as a first- or second-choice medication. One symptom this medication can be effective for is regulating your menstrual cycle.

Small studies have shown that metformin helps between 50% and 70% of women with irregular bleeding. That being said, it’s possible that taking metformin could change the frequency of your menstrual cycle if you have PCOS and haven’t gone through menopause. While this is the intended effect of using metformin to treat PCOS, it could come as a surprise if you’re not expecting it.

How long do metformin side effects last?

For most people, metformin side effects typically resolve within a few weeks and only occur when you first start the medication or when your dose is raised.

How can I avoid or alleviate metformin side effects?

For some people, metformin’s GI side effects may get better over time, but they don’t completely go away. So what can you do if diarrhea or nausea continues after a few weeks of being on a steady metformin dose? Below are three tips that may help.

1. Take your metformin with a meal

You’re less likely to experience problems if there’s food in your stomach. If you only take metformin once a day, take it with your biggest meal of the day. If you take it twice a day, try to take it at opposite ends of the day. For example, take it at breakfast and dinner instead of at lunch and dinner.

2. Switch to extended-release (ER) metformin

When people are first prescribed metformin, they usually get the immediate-release (IR) version. However, you are more likely to experience an upset stomach from it. The metformin ER tablets have a coating that releases the medication slowly and can make it less upsetting to the stomach. There are pros and cons to both versions. Talk to your healthcare provider about which is best for you.

3. Be careful with dietary changes and supplements

You may have read online that changing your diet or taking probiotics could help with an upset stomach. There’s actually no current evidence to support this. Changes to your diet should only be made when recommended by your healthcare provider or a dietician.

How often should I take metformin?

Normally, metformin ER is only taken once a day. Metformin IR and liquid metformin are usually taken multiple times a day.

If you do start taking metformin, how often you take it and your dose will depend on how you respond to it. Your healthcare provider should ask you for follow-up bloodwork in about 3 months to see if they should change your dose.

If you don’t follow the dosage instructions for metformin, it can lower the effectiveness of the medication and also make you more susceptible to side effects.

Try to take metformin at approximately the same time(s) every day. If you miss a dose, take it as soon as you remember. But if it’s almost time for your next dose, skip the dose you missed. Never double up on a dose to make up for missed doses.

What’s the best way to take metformin to avoid side effects?

Depending on which form of metformin you have, the way you take it will vary. But for both forms, it’s best to take them with food.

For the IR tabs, you can cut or crush them if swallowing them whole is difficult. Do not cut, crush, or chew the ER tablets; the coating must remain intact to work properly. In fact, it’s normal for the outer shell of the ER tablets to appear in your stool.

For the liquid version, make sure to use a dosage cup or syringe to measure out your dose. Using household spoons or teaspoons may be inaccurate.

If you aren’t sure of the best way to take metformin, speak to a pharmacist.

Can I take metformin with other medications?

Metformin interacts with a few medications. These medications can make metformin less effective or increase the risk of side effects. Notable medications that interfere with it include:

• Thiazide diuretics (hydrochlorothiazide, chlorthalidone)

• Corticosteroids (prednisone, methylprednisolone, dexamethasone)

• Estrogen-containing medications, including oral birth control pills and certain medications used to relieve menopause symptoms

• Carbonic anhydrase inhibitors (acetazolamide, zonisamide)

This is not a complete list of all drug interactions, so always check with your pharmacist or healthcare provider if you are concerned about potential interactions. If you are taking one of these other medications, you may be able to keep taking both. But you may need to have more frequent blood work to keep an eye on your blood sugar.

Drinking alcohol when taking metformin can lead to serious side effects

Drinking excessive amounts of alcohol while taking metformin is not safe. It can raise your risk of experiencing lactic acidosis. This is because metformin and alcohol both cause lactic acid to build up in the blood. As discussed above, too much lactic acid in the body can make you very sick.

So when you drink alcohol excessively and take metformin, your risk of lactic acidosis goes up. As always, it’s best to stay within the recommended low-risk limits for alcohol consumption: no more than 7 drinks per week for women (and no more than 3 drinks on any given day), and no more than 14 drinks per week for men (no more than 4 drinks on any given day).

However, everyone’s situation is different. For example, you may have health conditions that make combining alcohol with metformin even riskier. So, it’s best to speak with your healthcare provider about how much alcohol is safe for you to drink.

Side effects of stopping metformin

If you’re taking metformin to help control your blood sugar, it’s important to take it as prescribed. If you stop taking it, your blood sugar levels could get too high. If this happens, you may experience symptoms like dry mouth, feeling thirsty, or needing to pee more.

That said, there may be situations where your healthcare provider tells you to stop taking metformin. For example, symptoms of an allergic reaction or lactic acidosis are two situations where you should stop taking it and get emergency medical attention.