10 Important Side Effects of Metoprolol That You Need to Know

During physical activity, the body normally increases heart rate in response to increased demand.

A beta blocker limits this response.

Someone who previously relied on heart rate to judge exercise intensity may therefore notice that exercise feels different after starting metoprolol.

This does not necessarily mean exercise has become unsafe, but people with cardiovascular disease should follow individualized activity recommendations.
2. Dizziness or Lightheadedness

Metoprolol can lower blood pressure and slow the heart rate. Either effect can occasionally cause dizziness or lightheadedness.

This may be especially noticeable when:

Standing up quickly
Getting out of bed
Starting treatment
Increasing the dose
Exercising
Becoming dehydrated
Taking other blood-pressure-lowering medicines

Standing up gradually can sometimes reduce symptoms related to a sudden drop in blood pressure.

If dizziness is severe, frequent, or accompanied by fainting, chest pain, confusion, or difficulty breathing, medical evaluation is important.
Driving and Dizziness

Until you know how metoprolol affects you, be cautious with driving, operating machinery, or other activities in which dizziness or unusual fatigue could create a safety risk.
3. Slow Heart Rate

A slower heart rate is an expected pharmacological effect of metoprolol.

That is often one of the reasons the medication is prescribed.

However, in some people the heart rate can become slower than intended.

Possible symptoms associated with excessive slowing include:

Weakness
Dizziness
Fainting
Unusual fatigue
Shortness of breath
Reduced exercise tolerance
Confusion in some individuals

The meaning of a specific pulse rate depends on the individual. Athletes, for example, may naturally have relatively slow resting heart rates.

Do not change or skip your dose based only on one pulse reading unless a healthcare professional has specifically instructed you to do so.
When a Slow Heart Rate Needs Attention

A very slow pulse accompanied by fainting, severe weakness, difficulty breathing, chest discomfort, or confusion should be evaluated promptly.

Your clinician may review your dose and other medications that can also slow the heart.
Medicines That May Add to the Heart-Rate-Lowering Effect

Other drugs that affect heart rate or electrical conduction can sometimes amplify metoprolol’s effects.

This is why your doctor and pharmacist should know about every prescription medication, over-the-counter product, and supplement you take.

A slower pulse can be an intended effect of metoprolol, but slow heart rate plus fainting, severe weakness, or breathing difficulty is a different situation and should not simply be ignored.

4. Low Blood Pressure

Metoprolol is often prescribed specifically because it lowers blood pressure.

In some people, however, blood pressure can fall lower than intended.

Possible symptoms include:

Dizziness
Blurred vision
Feeling faint
Weakness
Confusion
Nausea
Unsteadiness

Low blood pressure becomes especially important when symptoms are severe or interfere with normal activities.
Why Low Blood Pressure May Be More Likely

The effect can become more noticeable when metoprolol is combined with other medicines that also lower blood pressure.

Dehydration, vomiting, diarrhea, fever, poor food and fluid intake, or excessive alcohol use can also contribute in some people.

If repeated blood pressure readings are unusually low for you and you feel unwell, contact your healthcare professional rather than adjusting medication independently.
Orthostatic Hypotension

Some people experience a drop in blood pressure when standing, known as orthostatic or postural hypotension.

Symptoms may include a brief wave of dizziness or blurred vision after getting up.

Rising slowly from bed or a chair may help.

Persistent episodes or fainting deserve medical assessment.
5. Cold Hands and Feet

Some people taking beta blockers notice that their fingers or toes feel colder than before.

This can happen because beta-blocker effects may alter blood flow in peripheral blood vessels.

For many people this is uncomfortable but not dangerous.

However, contact a healthcare professional if coldness is accompanied by:

Severe pain
Marked color changes
Numbness that persists
Wounds that heal poorly
A significant worsening of a known circulation problem

Metoprolol and Raynaud’s Symptoms

People with Raynaud’s phenomenon or significant peripheral vascular disease should mention this condition to their prescriber.

A healthcare professional can decide whether the benefits of treatment outweigh any potential worsening of peripheral symptoms.
6. Shortness of Breath or Wheezing

Metoprolol is considered relatively selective for beta-1 receptors in the heart, particularly at lower doses.

However, this selectivity is not absolute.

At higher doses, or in susceptible individuals, beta blockade can also influence beta receptors involved in airway function.

This can be important for people with asthma or other obstructive lung conditions.

Symptoms that deserve attention include:

New wheezing
Chest tightness
Increasing shortness of breath
Difficulty breathing
A noticeable reduction in the effectiveness of usual breathing treatments

Severe breathing difficulty requires urgent medical attention.
Does Asthma Mean Metoprolol Can Never Be Used?

Not necessarily.

The decision depends on the reason for treatment, severity of the lung disease, dose, and alternative options.

In some situations a clinician may still use a beta-1-selective blocker carefully.

This decision should be individualized rather than based on a blanket rule.
Do Not Assume Every Episode of Breathlessness Is a Side Effect