Metoprolol side effects and how to avoid them

Common metoprolol side effects | Serious side effects | Weight fluctuations | Memory loss | Hair loss | Rash | Side effects timeline | Contraindications | Warnings | Interactions | How to avoid side effects | How to treat side effects

Metoprolol (brand names: Lopressor, which is immediate-release metoprolol, and Toprol XL, which is extended-release metoprolol) is a generic prescription drug used to treat high blood pressure, treat chest pain (angina), or increase the chances of survival in the weeks and months after a heart attack. The extended-release form of Toprol XL can also be used to treat heart failure. These are the FDA approved uses of metoprolol, but healthcare professionals commonly prescribe it off-label for other medical conditions such as preventing migraine headaches. Belonging to a family of drugs called beta blockers, metoprolol lowers blood pressure by widening blood vessels. It also slows down the heart. This both reduces blood pressure and eases the stress on the heart. Not surprisingly, some of the most common and concerning side effects of metoprolol are related to low blood pressure and heart problems.

Common side effects of metoprolol

Whether taken as immediate-release tablets (metoprolol tartrate) or extended-release tablets (metoprolol succinate), metoprolol’s most common side effects include:

• Tiredness
• Dizziness
• Diarrhea
• Itchiness
• Rash
• Depression
• Trouble breathing
• Slow heart rate
• Low blood pressure (hypotension)
• Trouble sleeping
• Nightmares

Serious side effects of metoprolol

Metoprolol can cause serious side effects including:

• Dangerously slow heartbeat (severe bradycardia)
• Heart failure
• Heart block
• Cardiogenic shock
• Cardiac arrest
• Heart attack (when the drug is abruptly stopped)
• Irregular heartbeats  (when the drug is abruptly stopped)
• Wheezing (bronchospasm)
• Allergic reactions

The incidence of some of these serious adverse effects is closely related to the condition being treated. Some are highly unlikely in people only being treated for hypertension. The prescribing healthcare provider can help patients understand the likelihood of serious problems when taking metoprolol.

Weight fluctuations

Beta blockers such as metoprolol have been associated with weight gain ranging from insignificant to almost 10 pounds after a year of treatment. Most of the weight gain tends to occur in the first few months. Weight gain may not be ideal for people with high blood pressure, heart problems, or diabetes, so patients should talk to a registered dietician at the onset of metoprolol treatment.

Memory loss

Metoprolol can affect the nervous system, causing several issues including sleeping problems and vertigo. Beta blockers other than metoprolol have also caused problems such as depression, disorientation, and memory loss, but many of these other beta blockers pass more readily than metoprolol into the brain. Theoretically, metoprolol could cause these same problems including memory loss, but these are less common in metoprolol patients.

Hair loss

There have been rare reports of people losing their hair while taking metoprolol. This hair loss is reversible if metoprolol is discontinued. If hair loss should occur, it’s likely the prescribing healthcare provider will stop metoprolol treatment. 

Rash

In clinical studies, about five in 100 patients taking metoprolol reported mild allergic reactions such as rash and itching. When taking any drug, people should immediately report even the mildest hypersensitivity reactions to the prescribing healthcare provider. Serious allergic reactions, with symptoms of hives, difficulty breathing, or swelling of the face, lips, tongue, or throat, require emergency medical attention. 

How soon do metoprolol side effects start?

Some side effects, such as allergic reactions, may happen within hours of taking the first metoprolol tablet. Metoprolol’s beta-blocking effects typically occur about an hour after taking a dose and hit their peak about 30 minutes later, so side effects related to beta blockade may also be experienced early. Other side effects, such as weight gain, typically take several months to become apparent.

How long do metoprolol side effects last?

Most people will experience minor and reversible side effects when taking metoprolol. Some of these problems will get better as the body adjusts to the drug, and most will go away after the drug has been discontinued. However, some side effects, such as a worsening of angina, occur only when metoprolol is stopped suddenly. Other side effects, such as weight gain, may require treatment and take longer to resolve. Some of the most serious but rare side effects such as heart failure, cardiogenic shock, and heart attack, may have lifelong consequences.

What are the long-term side effects of metoprolol?

In some cases, metoprolol can cause problems that cannot be reversed by discontinuing the drug. These are, fortunately, rare, and typically associated with people taking metoprolol for heart attack. Most of these problems are heart-related: heart attack, cardiogenic shock, heart block, and heart failure. However, in clinical trials, these events occurred only slightly more often or less often in people taking metoprolol compared to those given a placebo.

Metoprolol contraindications

As with all prescription medications, metoprolol is not suitable for everyone. Pre-existing medical conditions can increase the risk of problems, so anyone with the following problems cannot safely take metoprolol:

• Serious heart problems: Slow heart rate, heart block, decompensated heart failure, and heart rate irregularities (sick sinus syndrome) all increase the likelihood that metoprolol will cause severe heart problems. Healthcare providers will also avoid giving metoprolol as a heart attack treatment to any person with moderate to severe heart failure.
• Low blood pressure: If systolic blood pressure (the top blood pressure number) is too low, metoprolol will be avoided.
• Allergic reactions to metoprolol or other beta blockers.
• Severe problems with blood vessels.

Metoprolol warnings

People using metoprolol should not be overly concerned about serious problems with the drug itself. Metoprolol has a boxed warning, which is the most serious warning by the Food and Drug Administration (FDA). The warning states that metoprolol should not be abruptly discontinued in patients with coronary artery disease, because it can cause worsening of chest pain, heart attack, or irregular heartbeat. If/when metoprolol is discontinued, the healthcare provider will give the patient a tapering schedule and monitor the patient closely.  

In certain cases, pregnant and nursing women may be given metoprolol, but anyone who is pregnant, trying to become pregnant, or breastfeeding should tell the prescriber before taking this drug. 

Metoprolol recalls are rare and have been limited to manufacturing problems by individual generic manufacturers rather than actual problems with the drug itself. Metoprolol has not been associated with drug abuse, dependency, or withdrawal. 

However, taking too much metoprolol can cause serious problems including heart failure, heart attack, and death. Symptoms of an overdose include slowed heart rate, low blood pressure, and wheezing. If a patient or caretaker suspects that too much metoprolol has been taken, seek emergency medical treatment.

Metoprolol can be taken safely by many people with pre-existing conditions, but certain conditions may require extra monitoring. These include:

• Cardiovascular problems such as heart failure, coronary artery disease, first-degree heart block, irregular heartbeats, or problems with peripheral blood vessels. Metoprolol may worsen these conditions.
• People withg diabetes require closer monitoring of blood glucose levels, because metoprolol may mask some symptoms of low blood sugar.
• People with asthma or similar lung problems will need to be monitored for breathing issues.
• People with liver problems may require dose adjustments because their body does not eliminate metoprolol as efficiently as other people. Without a dose adjustment, higher concentrations of metoprolol will accumulate in the body, making side effects more likely.
• Older patients, too, are more likely to eliminate the drug slowly and have higher-than-normal concentrations of metoprolol in their blood. A lower starting dose is recommended.
• People with angina will generally take tapering doses when metoprolol is stopped. If discontinued abruptly, metoprolol can cause chest pain to worsen.

Metoprolol interactions

As with other prescription drugs, many problems with metoprolol can occur due to drug interactions. Most of these problems are additive: combining metoprolol with these drugs amplifies the effects of one or both drugs. None of these other drugs are strictly prohibited, but a healthcare provider will watch more closely for side effects or other problems. Drugs that are significant include:

• Other beta blockers such as atenolol or propanolol
• Other blood pressure drugs, particularly certain calcium channel blockers and alpha blockers
• Digitalis medications such as digoxin that treat heart failure and irregular heart rate
• Migraine drugs (ergots and triptans)
• NSAIDs
• Certain types of allergy medications like epinephrine
• Drugs that interfere with the body’s ability to metabolize metoprolol (CYP2D6 inhibitors)
• Foods that lower blood pressure such as garlic and flaxseed.

There is one drug called Marplan (isocarboxazid), an older antidepressant, that is never prescribed with blood pressure drugs. This restriction includes beta blockers like metoprolol. It’s not the most common antidepressant, but it’s generally a good idea to tell the prescribing healthcare provider about any antidepressants that are being taken. Many types of antidepressants, such as SSRIs including Paxil (paroxetine) and Prozac (fluoxetine), could interfere with the body’s ability to break down and eliminate metoprolol and so increase the risk of serious side effects.

How to avoid metoprolol side effects

Metoprolol is a life-saving drug. Fortunately, most people taking the drug for hypertension or chest pain will experience only minor problems. There’s a greater risk of severe problems when metoprolol is used to treat heart attack, but these effects do not compare with the immediate risks that follow from a heart attack. For all people, however, there are a few common-sense strategies to minimize metoprolol side effects.

1. Tell the healthcare provider about all medical conditions

The most certain way to prevent side effects from any drug is to make sure the prescribing healthcare provider is well-informed about current and past medical conditions. For metoprolol, make sure the healthcare provider knows about:

• Heart disease
• Circulation problems
• Asthma or COPD
• Liver disease
• Diabetes or thyroid problems
• Pheochromocytoma (adrenal gland tumor)
• Any upcoming major surgery
• Pregnancy or any plans to become pregnant

2. Tell the healthcare provider about all medications being taken

Make sure your prescriber knows about all prescription drugs, over-the-counter medications, and vitamins or supplements being taken. The most important are:

• Blood pressure drugs
• Heart rhythm drugs like digoxin
• Migraine drugs
• NSAIDs
• Antidepressants

3. Take metoprolol as directed

Follow the directions given by the prescriber or printed on the prescription label. Do not take more than directed or reduce the dose.

4. Don’t miss a dose

Taking too much metoprolol will cause side effects, and a common way to take too much is to miss a dose of metoprolol (and then try to make up for it by taking two doses close together). Use alarms or phone apps to help take doses. In case of a missed dose, take the dose when remembered, but avoid taking it when the next dose is soon to be taken. Don’t take a double dose to make up for a missed dose.

5. Check blood pressure often

When taking any blood pressure medication, it’s a good idea to purchase a blood pressure monitor and check blood pressure regularly. Share your readings with your healthcare provider. Always do a blood pressure reading at any sign of hypotension (low blood pressure) such as dizziness, lightheadedness, or fainting.

6. Stand up and move slowly

Any dizziness or lightheadedness experienced while taking metoprolol can be minimized by moving carefully and standing up slowly. This will help prevent fainting and falls.

7. Avoid alcohol

Alcohol is not prohibited, but it may be a good idea to stop drinking if there are problems like dizziness or low blood pressure when taking metoprolol. People taking extended-release metoprolol will be counseled to avoid alcohol entirely. 

8. Avoid driving at first

Metoprolol may affect a person’s ability to safely drive or engage in potentially risky activities like operating machinery or sports. To prevent possibly serious problems, healthcare professionals will advise patients to hold off on driving, operating machinery, or other risky activities until the effects of the drug are understood.

How to treat side effects of metoprolol

Most people will only experience minor problems with metoprolol. Many side effects will improve over time, and others can be treated by making lifestyle changes to either adapt or prevent these side effects. For instance, dizziness and lightheadedness can’t be treated, but people who experience them should take precautions such as removing obstacles in the home or moving (and standing up) slowly. Avoiding driving and dangerous activities is also a good idea. People experiencing weight gain should consult with a registered dietician to help slow or stop the weight gain.

Other side effects will require medical treatment or, at the very least, the medical advice of a healthcare professional. The most serious side effects are known primarily by their symptoms, so talk to a healthcare provider if any of these are experienced:

• Signs of an allergic reaction

• Hives
• Swelling of the face, lips, tongue, or throat
• Trouble breathing
• Trouble swallowing

• Signs of heart problems
• Very slow heartbeats
• Severe dizziness or lightheadedness
• Shortness of breath
• Rapid weight gain
• Swelling
• Nervous system problems
• Depression
• Disorientation
• Confusion
• Memory loss