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.
