Metoprolol is a prescription drug that doctors may use to treat heart issues, such as high blood pressure, heart attack, and heart failure. The most common form is metoprolol succinate, which people can buy under the brand name Toprol-XL. Metoprolol may also refer to metoprolol tartrate, which has the brand name Lopressor.

Metoprolol often causes side effects so some people may wish to consider using alternative medications.

Importantly, no one taking metoprolol should stop taking the drug unless they are following direct orders from a doctor. Even if the drug causes side effects, the person will need to come off the drug gradually or transfer to a new drug.


Senior woman holding bottle of pills in front of tablet.
Metoprolol can help treat a range of conditions, including angina and high blood pressure.

Metoprolol often features in treatment plans for high blood pressure and angina, a type of chest pain. The type of metoprolol will determine its other uses.

For example, metoprolol tartrate may help prevent a heart attack in people with heart disease or those who have already had a heart attack. However, metoprolol succinate will not help prevent heart attacks from occurring.

In some cases, doctors may also prescribe the drug as a way to prevent migraines.

How it works

Metoprolol is a cardioselective beta-blocker. Beta-blockers prevent the heart from getting too excited or overworked. They do this by blocking off the beta receptors in the blood and heart.

When the receptors are inaccessible, compounds that would usually excite the heart, such as epinephrine, cannot act on them and cause these effects. As a result, this may help keep the blood vessels relaxed.

When the blood vessels are relaxed, the heart does not have to work as hard to pump blood, which can help lower a person’s heart rate. Beta-blockers may also reduce how much oxygen the heart requires and lessen the need for it to pump faster.

This combination of effects is what helps reduce the symptoms of heart problems, including high blood pressure and angina.

How to take it

The required dosage of each drug will differ from person to person as it will depend on a few different factors, including the condition that requires treatment. It is important to follow the dosing instructions that the doctor provides.

In some cases, doctors may prescribe a low dose of the drug initially and then increase it incrementally to find the smallest effective dose that still relieves symptoms.

As the Toprol-XL label states, the individual should take the extended-release metoprolol succinate tablet regularly and continuously, once each day, and preferably with or just after a meal.

If the person misses a dose, they should not take a double dose but should take the next tablet as usual the following day.

Side effects

Side effects of metoprolol can include shortness of breath, dizziness, and fatigue.
Side effects of metoprolol can include shortness of breath, dizziness, and fatigue.

Metoprolol may cause side effects, the severity of which can vary between people. Common side effects include:

  • dizziness
  • fatigue
  • constipation
  • diarrhea
  • shortness of breath
  • coughing or wheezing
  • skin rashes
  • temporary mental confusion
  • blurry vision
  • short-term memory loss
  • reduced sex drive or loss of interest in sex

Many of these side effects will be temporary and may be relatively mild.

More severe side effects are also possible when using metoprolol, although they are generally less common. They include:

  • an allergic reaction, which may cause itching of the throat and swelling of the face, throat, or hands
  • cold hands or feet that may feel numb
  • extremely low or slow heart rate or weak pulse
  • extreme fatigue that may get worse over time
  • trouble concentrating
  • symptoms of depression, such as continuous or recurring feelings of sadness

Anyone experiencing serious side effects from metoprolol should contact their doctor immediately. If the symptoms feel life-threatening or the person loses consciousness, they need emergency medical attention.


Metoprolol interacts with several drugs. People who are taking the drug or may need to should review their other medications with a doctor first to check for any interactions.

The same goes for vitamins, supplements, and over-the-counter medications that the person may also be taking. A few different types of drug interact with metoprolol.

Monoamine oxidase inhibitors

Doctors often prescribe monoamine oxidase inhibitor (MAOI) drugs for mental health issues. These drugs may add to the effects of metoprolol, which may put the person at risk of complications, such as those that result from an extremely low heart rate.

Some common MAOI drugs include:

  • tranylcypromine (Parnate)
  • isocarboxazid (Marplan)
  • selegiline (Emsam)
  • phenelzine (Nardil)

Selective serotonin reuptake inhibitors

Some selective serotonin reuptake inhibitor (SSRI) antidepressant drugs may also affect how metoprolol works.

The body may process these drugs in a similar way to metoprolol, which could increase the amount of the drug in the body or its effectiveness. These drugs include:

  • paroxetine (Paxil)
  • sertraline (Zoloft)
  • fluoxetine (Prozac)


In some cases, the person may already be taking a medication that could interfere with metoprolol. For instance, doctors often prescribe alpha-blockers for high blood pressure.

If the individual takes the drugs together, the effect may be too significant, putting the person at risk of issues resulting from low blood pressure.

Alpha-blockers include the following drugs:

  • clonidine (Catapres)
  • terazosin (Hytrin)
  • prazosin (Minipress)

Other drugs

Other drugs that may interact with metoprolol include:

  • antihistamine drugs, such as diphenhydramine (Benadryl)
  • some antifungal and antimalarial drugs
  • hydralazine, a drug for blood pressure
  • ritonavir, a drug that people use to treat HIV
  • some herbs, such as St. John’s wort

Alcohol could also lower a person’s blood pressure and increase some of the effects of the drug. Doctors are likely to advise the individual about alcohol consumption, and they may recommend that a person stops drinking while taking the medication.

It is essential to note that this is not a complete list of interactions. Anyone with a metoprolol prescription should have a thorough discussion with their doctor about any other drugs or supplements that they are taking to avoid potentially serious complications.


A doctor can explain the risks of metoprolol.
A doctor can explain the risks of metoprolol.

There are a few important warnings to consider when taking metoprolol.

The drug has a United States Food and Drug Administration (FDA) black box warning, which is the most serious warning that a drug can receive. The FDA note that people who take beta-blockers and then abruptly stop might have a higher risk of issues relating to the heart.

Unless a doctor gives a direct order, do not suddenly stop using metoprolol. Doing so may cause a sharp increase in blood pressure, and it could significantly increase the risk of symptoms returning or the person having a heart attack.

There are additional factors to consider when using the drug.

It is crucial to take the drug exactly as the doctor advises. Taking too much of the drug or taking it too often may lead to a drug overdose, which could reduce the heart rate to dangerous levels and lead to hospitalization.

Anyone who thinks that they have taken too much of the drug should seek emergency medical attention.

In some cases, the drug may cause a severe allergic reaction. Signs of an allergic reaction include:

  • swelling of the face, tongue, or throat
  • itching in the throat
  • difficulty breathing

Anyone experiencing these symptoms should also seek emergency medical attention.

Metoprolol can cross the placenta and enter the breast milk. Therefore, anyone who is pregnant or breastfeeding should discuss all options and possibilities with their doctor before using metoprolol.

There may also be a link between metoprolol and drug-induced liver injury, although reported cases are rare. People who have issues with their liver may need to be cautious when using the drug.

Considerations for certain health conditions

People with certain health conditions should be aware of the risks when taking the drug, while others should not take it at all.

  • Poor circulation. People with circulation issues, such as difficulty getting fresh blood into the legs and hands, may need to consider other options. Metoprolol could make circulation issues worse.
  • Major surgery. People who are about to have major surgery should not start taking the drug as it may lead to severe complications.
  • Diabetes. People with diabetes may need to take extra care to monitor their blood sugar levels when using the drug. Metoprolol may hide some of the signs of low blood sugar, such as increased heart rate.
  • COPD or asthma. People with conditions that cause muscle walls deep in the lungs to spasm, such as COPD or asthma, should usually avoid taking beta-blockers.

However, the FDA note that in some cases of COPD and asthma, it is necessary to use metoprolol if the person does not respond well to other treatments. Doctors will monitor these individuals closely to check for any complications.

Alternative drugs

There are a few alternatives to metoprolol. The alternatives available to someone will depend on many factors, such as other medications that they are taking, any medical conditions that they have, and their reason for needing the drug in the first place.

Anyone who thinks that metoprolol is not right for them should talk to their doctor about possible alternatives. It is vital never to stop taking the drug suddenly.


Metoprolol is a drug that may help many people control potentially dangerous symptoms of the heart and circulatory system.

A person should consider many factors before starting the drug, including potential side effects and any other medications that they are taking. As always, it is best to discuss possible complications and alternative treatment options with a doctor.