Metoprolol is a prescription medicine that belongs to a group of medicines called beta-blockers. It is commonly used to treat high blood pressure, chest pain associated with angina, certain heart-rhythm problems, and some forms of heart failure. It may also be prescribed after a heart attack.

Because metoprolol changes the way the heart works, it is important to understand both its expected effects and its possible side effects. Many people take metoprolol without experiencing serious problems, but some symptoms should not be ignored.

One important point about the image accompanying this topic: the bottle shown in the image is labeled amlodipine 5 mg, not metoprolol. Amlodipine and metoprolol are different medications and can have different side effects. The information below is specifically about metoprolol.

How Metoprolol Works

Metoprolol works by blocking some of the effects of adrenaline and other stress hormones on the heart. As a result, the heart generally beats more slowly and with less force, while blood pressure can decrease.

This action can be beneficial for people who need to reduce the workload on their heart. However, the same effects can sometimes produce symptoms such as tiredness, dizziness, or a slower heart rate.

Metoprolol comes in different forms, including immediate-release and extended-release formulations. The exact instructions depend on which formulation has been prescribed and why it is being used.

It should always be taken exactly as prescribed.

1. Dizziness or Lightheadedness

One of the more common effects people may notice while taking metoprolol is dizziness or lightheadedness.

Because the medicine can lower heart rate and blood pressure, some people may feel dizzy, particularly when standing up quickly from a sitting or lying position.

This may be more noticeable when someone has recently started treatment or when the dose has been changed.

If you feel dizzy, sit or lie down until the sensation passes. Stand up slowly and give your body a moment to adjust.

Persistent or severe dizziness should be discussed with a healthcare professional, especially if it interferes with normal activities.

If dizziness is accompanied by fainting, chest pain, severe weakness, or difficulty breathing, urgent medical attention may be necessary.

2. Unusual Tiredness or Fatigue

Feeling tired is another possible side effect.

Because metoprolol slows the heart rate and reduces the effects of adrenaline, some people may initially notice that they have less energy than usual.

You may feel tired when doing activities that previously felt easy, or you may feel unusually sleepy during the day.

For some people, this improves as the body adjusts to the medication.

However, extreme or worsening fatigue should not simply be ignored. It can sometimes indicate that the heart rate or blood pressure is lower than appropriate, or that another medical problem is contributing to the symptom.

If your tiredness is severe or persistent, speak with your healthcare professional rather than changing your dose yourself.

3. Slow Heart Rate

Metoprolol is designed to slow the heart rate, so a slower pulse can be an expected effect.

However, a heart rate that becomes excessively slow can cause problems.

Possible symptoms may include:

Dizziness
Weakness
Extreme fatigue
Lightheadedness
Fainting
Shortness of breath
Difficulty exercising

People respond differently to beta-blockers, so there is not one single heart-rate number that is automatically dangerous for everyone.

If you notice a significant change in your pulse together with symptoms, contact your healthcare professional.

Never adjust your metoprolol dose simply because you notice that your heart rate is lower unless your prescriber has given you specific instructions for doing so.