Key takeaways:
Metoprolol (Lopressor) is a beta blocker that treats high blood pressure and other heart conditions. The most common side effects of metoprolol are dizziness, tiredness, and diarrhea. Other metoprolol side effects include itchiness and depression.
In rare cases, metoprolol may cause more serious side effects, such as very low heart rate or worsening of lung conditions. It can also mask symptoms of low blood glucose (sugar).
If you experience severe fatigue, shortness of breath, or unexpected weight gain and swelling, contact your prescriber immediately. This could indicate heart or lung problems. If symptoms feel severe, seek emergency care.
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Metoprolol is a beta blocker that’s FDA approved to treat high blood pressure and chest pain (angina). The immediate-release (IR) version, known as metoprolol tartrate (Lopressor), is also FDA approved to prevent death after a heart attack. And the extended-release (ER) versions, known as metoprolol succinate (Toprol XL, Kapspargo Sprinkle), are approved to lower the risk of death and hospitalization in people with heart failure.
Although there are some differences between the two versions of metoprolol, they have similar risks. In fact, all beta blockers share some common side effects. And knowing which metoprolol side effects to watch for can help you prevent or manage them.
Keep in mind: This article focuses on metoprolol IR. Check out another GoodRx Health article for more information on metoprolol ER side effects.
Metoprolol side effects at a glance
Metoprolol is typically well tolerated. Common side effects are usually mild and tend to go away as your body gets used to the medication. Metoprolol may also have some side effects that can be serious, although these are rare.
Common metoprolol side effects include:
Dizziness
Low blood pressure
Fatigue
Itchiness
Mood changes
Nausea
Diarrhea
Headache
Rare but serious metoprolol side effects include:
Masking symptoms of low blood glucose (sugar)
Masking signs of hyperthyroidism
Extremely low heart rate
Worsening heart failure, heart block, or peripheral artery disease
Worsening lung conditions, such as asthma or chronic obstructive pulmonary disease (COPD)
Below, we’ll go into more detail about eight of these metoprolol side effects and how to manage them.
1. Dizziness and low blood pressure
Dizziness is one of the most common metoprolol side effects. This can occur because metoprolol lowers blood pressure. Usually, this is a good thing. But in some cases, it may cause your blood pressure to drop too low (hypotension), leading to dizziness and lightheadedness.
Low blood pressure with metoprolol typically improves as your body gets used to the medication. You can also take a few steps to help lessen dizziness if you’re experiencing it, such as:
Change positions slowly and hold onto something steady, such as a stable piece of furniture.
If you feel dizzy as you stand up, sit back down until the dizziness passes. Then, try to stand again.
If you’re lying down, sit up first and wait a minute or two before slowly standing.
If you have dizziness that disrupts your day-to-day life or doesn’t go away after a few weeks, talk with your prescriber. They can check your blood pressure. If it’s too low, they may lower your metoprolol dosage or consider whether something else may be causing your dizziness.
2. Tiredness
Along with dizziness, tiredness is one of the most common side effects of metoprolol. This may occur because metoprolol slows your heart rate, which can make you sleepy. Metoprolol also passes into the brain, which may be another reason it makes you tired.
Like other common metoprolol side effects, fatigue and drowsiness should improve as your body adjusts to the medication. There are also a few things you can do to help relieve fatigue.
Stay active: It may seem counterintuitive, but regular exercise can help increase your energy levels. Talk with your healthcare team about what your target heart rate should be during exercise.
Eat a healthy diet: Nutrient-rich foods can help boost your energy level. Some examples include fatty fish, berries, and beans.
Maintain a regular sleep schedule: Getting adequate sleep can help minimize fatigue. Depending on your age, you may need 7 or more hours of sleep each night. Avoiding caffeine in the late afternoon or evening and sticking to a regular bedtime routine can help improve your sleep.
3. Diarrhea
Diarrhea is another possible metoprolol side effect.
If you have diarrhea with metoprolol, there are some things you can do to prevent it from getting worse. These include avoiding foods that can cause diarrhea, such as fried or fatty foods. And drinking plenty of fluids, such as water and electrolyte drinks, can help you avoid dehydration from diarrhea.
Simple measures like these may not always be enough. If you need more relief, over-the-counter (OTC) medications like loperamide (Imodium A-D) may help. But it’s best to check with a healthcare professional before trying one.
If your diarrhea continues longer than a few days, let your prescriber know. They may want to consider whether something else could be the cause.
4. Itchiness
Some people may experience itchiness or a rash while taking metoprolol. In most cases, itchiness is mild and temporary.
However, itchiness with a rash may also be a symptom of an allergic reaction. Let your prescriber know right away if you have severe itchiness or a sudden rash while taking metoprolol.
Call 911 or seek immediate emergency care if you have symptoms of a serious allergic reaction, such as trouble breathing or swelling of your face or throat.
5. Depression
Depression has also been reported with beta blockers. However, research in the past few years has shown that beta blockers may not be as likely to cause depression as we thought. Still, it’s important to let your prescriber know if you have a history of depression before you start taking metoprolol. They can help you decide if metoprolol is right for you.
To be safe, tell your prescriber if you experience new or worsening depression symptoms while taking metoprolol. These may include:
Persistent feelings of sadness or hopelessness
Sleeping more or less than usual
Trouble concentrating
Suicidal thoughts or actions
If you or someone you know is having thoughts of suicide, you’re not alone, and help is available. Call the 988 Suicide & Crisis Lifeline at 988, or text “HOME” to 741-741 to reach the Crisis Text Line.
6. Hypoglycemia
Metoprolol doesn’t directly lower your blood sugar. However, it can make it harder to notice if you’re experiencing hypoglycemia (low blood sugar).
Metoprolol slows your heart rate. This can mask several signs of hypoglycemia such as a fast heart rate, shakiness, and nervousness. However, other signs and symptoms of hypoglycemia, such as dizziness, sweating, and confusion may still be present. Watching for these symptoms is important, especially if you are taking medication to treat diabetes or prediabetes.
If you have diabetes, it’s a good idea to test your blood sugar regularly. So talk to your prescriber about your individual blood sugar goals. Typically, if your blood sugar is below 70 mg/dL or you have symptoms of hypoglycemia, you should treat it with a quick-acting sugar source, such as ½ cup of non-diet juice or soda or 4 glucose tablets.
7. Heart problems
Metoprolol works by slowing your heart rate and lowering your blood pressure. In rare cases, this can sometimes cause heart problems (or make existing heart issues worse). Metoprolol may slow your heart rate too much, causing what’s known as bradycardia.
In severe cases, bradycardia may cause symptoms and require medical attention. Symptoms may include:
Dizziness
Chest pain
Weakness or fatigue
Fainting
Shortness of breath
Bradycardia can also make heart failure worse. In fact, people with severe heart failure should typically avoid metoprolol. So if you notice any symptoms of worsening heart failure, such as unexplained weight gain or swelling, talk to your prescriber immediately. You may need a lower metoprolol dose, or they may need to adjust the doses of your other heart failure medications.
8. Worsening lung conditions
If you have lung problems, such as asthma or chronic obstructive pulmonary disease (COPD), beta blockers may not be the best choice for you. This is because they can worsen these conditions. However, beta blockers that mainly affect the heart (including metoprolol), may be safe for people with mild lung conditions. For others, it may be too risky.
Let your prescriber know if you have asthma or COPD before taking any beta blocker. They can decide if it’s safe for you.
Frequently asked questions
No, metoprolol isn’t usually considered a high-risk medication. But it still needs to be taken carefully. Taking too much could cause a very slow heart rate, low blood pressure, or fainting. You also shouldn’t stop taking it suddenly. This could lead to serious heart problems too. So it’s important to take it exactly as prescribed.
Metoprolol is sometimes linked to ankle swelling. But it’s uncommon overall and isn’t always caused by the metoprolol specifically. If swelling is new or getting worse, contact a healthcare professional right away — especially if you also notice shortness of breath or sudden weight gain.
No, metoprolol isn’t usually considered a high-risk medication. But it still needs to be taken carefully. Taking too much could cause a very slow heart rate, low blood pressure, or fainting. You also shouldn’t stop taking it suddenly. This could lead to serious heart problems too. So it’s important to take it exactly as prescribed.
Metoprolol is sometimes linked to ankle swelling. But it’s uncommon overall and isn’t always caused by the metoprolol specifically. If swelling is new or getting worse, contact a healthcare professional right away — especially if you also notice shortness of breath or sudden weight gain.
The bottom line
Metoprolol tartrate (Lopressor) is a beta blocker that treats high blood pressure and other heart conditions. Some of the most common metoprolol side effects include dizziness, tiredness, and diarrhea. Other side effects of metoprolol include itching and depression.
Metoprolol side effects are typically mild and may improve as your body adjusts to the medication. Serious side effects are rare, but can include worsening heart and lung problems. Metoprolol can also mask the symptoms of low blood glucose (sugar).
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References
American Heart Association. (2021). Beta-blockers not likely to cause depression yet may contribute to sleep disturbances.
MedlinePlus. (2026). Metoprolol.
Shah, R., et al. (2020). Metoprolol-associated central nervous system complications. Cureus.
Westminster Pharmaceuticals. (2025). Metoprolol tartrate- metoprolol tartrate tablet [package insert].
