Metoprolol is a commonly prescribed medication known as a beta blocker. Doctors may prescribe it for conditions such as high blood pressure, certain heart rhythm problems, angina, and some forms of heart failure. Depending on the formulation, it may also be used after a heart attack.
Like all medications, metoprolol can cause side effects. Many are mild and may improve as the body adjusts to treatment, but some symptoms can signal a more serious problem.
If you take metoprolol, knowing what to watch for can help you recognize when to contact your healthcare professional.
What Is Metoprolol?
Metoprolol works mainly by blocking the effects of certain stress hormones, particularly adrenaline, on the heart. This slows the heart rate and can reduce blood pressure and the heart’s workload.
There are two commonly used forms:
- Metoprolol tartrate, usually taken more than once a day depending on the prescription
- Metoprolol succinate extended-release, generally taken once daily
They are not interchangeable on a milligram-for-milligram basis, so patients should take exactly the formulation and dose prescribed by their healthcare professional.
10 Possible Side Effects of Metoprolol
1. Tiredness or Fatigue
Feeling unusually tired is one of the side effects people may notice when starting metoprolol.
Because the medicine slows the heart rate and reduces the effects of adrenaline, some people may initially feel less energetic than usual.
For many patients, this improves as the body adjusts. However, severe or persistent fatigue should be discussed with a healthcare professional.
2. Dizziness or Lightheadedness
Metoprolol can lower blood pressure and slow the heart rate, which may cause dizziness or lightheadedness.
This may be particularly noticeable when standing up quickly.
If you feel dizzy, sit or lie down until the sensation passes. Repeated or severe dizziness should be reported to your doctor, especially if you feel close to fainting.
3. Slow Heart Rate
Because metoprolol is designed to slow the heart, a lower pulse can be an expected effect.
However, a heart rate that becomes unusually slow—especially when accompanied by weakness, dizziness, fainting, confusion, or shortness of breath—may require medical evaluation.
Do not change your dose based solely on a home pulse reading unless your healthcare professional has given you specific instructions for doing so.
4. Low Blood Pressure
Metoprolol can lower blood pressure.
This is often part of the reason it is prescribed, but blood pressure that becomes too low may cause:
- Dizziness
- Weakness
- Blurred vision
- Lightheadedness
- Fainting
If these symptoms occur frequently, contact your healthcare professional.
5. Cold Hands and Feet
Some people taking beta blockers notice that their hands or feet feel colder than usual.
This may happen because beta blockers can affect circulation to the extremities.
If you develop severe pain, marked color changes, numbness, or persistent symptoms, seek medical advice.
6. Sleep Disturbances or Unusual Dreams
Some people report sleep-related effects while taking beta blockers, including difficulty sleeping or unusually vivid dreams.
Not everyone experiences these effects, and sleep problems can have many other causes.
If insomnia or disturbing dreams become persistent, discuss them with your healthcare professional rather than stopping the medication on your own.
7. Nausea or Stomach Discomfort
Metoprolol can sometimes cause digestive symptoms such as nausea or stomach discomfort.
Taking the medication exactly as directed may help, depending on the formulation and your doctor’s instructions.
Persistent vomiting or severe abdominal symptoms should be evaluated because they may have another cause.
8. Shortness of Breath or Breathing Problems
Breathing difficulties should not automatically be dismissed as a routine side effect.
Beta blockers can sometimes cause problems in susceptible individuals, particularly people with certain airway conditions. Metoprolol is relatively selective for beta-1 receptors at usual doses, but that selectivity is not absolute.
If you develop new or worsening breathing difficulty, wheezing, or chest tightness, contact a healthcare professional promptly.
Severe difficulty breathing is an emergency.
9. Depression or Mood Changes
Some people report mood changes while taking beta blockers, although the relationship between beta blockers and depression is complex and not clearly established in every patient.
If you experience significant changes in mood, persistent sadness, unusual behavior, or other concerning psychological symptoms, tell your healthcare professional.
Never stop a prescribed heart medication abruptly because of a suspected side effect without medical guidance.
10. Sexual Problems
Some people taking beta blockers report sexual side effects, including reduced sexual desire or difficulty achieving or maintaining an erection.
However, sexual problems can also be caused by cardiovascular disease, diabetes, stress, hormonal changes, and other medications.
If this occurs after starting metoprolol, discuss it with your healthcare professional. There may be ways to manage the problem without