Metoprolol

Key facts

• Metoprolol (brand names Lopressor and Toprol XL) is a beta-blocker that slows the heart rate and reduces the force of each heartbeat, lowering blood pressure and the heart's oxygen demand.
• It's taken once or twice daily depending on the formulation, and regular tablets need consistent timing to keep levels steady.
• Never stop metoprolol abruptly. Doing so can cause a rebound in heart rate and blood pressure and can trigger angina, a heart attack or a dangerous arrhythmia, especially if you already have heart disease. The dose must be reduced gradually, usually over 1 to 2 weeks.
• Seek urgent care for a resting heart rate under 50 beats per minute, fainting, or worsening shortness of breath and swelling.

What metoprolol treats

Metoprolol treats high blood pressure, angina (chest pain from reduced blood flow to the heart), and certain fast or irregular heart rhythms. It's also used to reduce the risk of death after a heart attack and, in extended-release form, to manage stable heart failure by easing the heart's workload.

How metoprolol works

Metoprolol blocks beta-1 receptors in the heart that normally respond to adrenaline. With those receptors blocked, the heart beats more slowly and with less force, which lowers blood pressure and reduces how much oxygen the heart muscle needs.

Before you take it

• Avoid metoprolol if you have a very slow heart rate, certain heart block conditions, or uncontrolled heart failure, unless a cardiologist directs otherwise.
• Tell your prescriber about asthma or COPD; beta-blockers can narrow the airways and worsen breathing difficulty.
• If you have diabetes, know that metoprolol can mask the early warning signs of low blood sugar, such as a racing heart.
• Combining metoprolol with other heart-rate-lowering drugs, such as verapamil or diltiazem, can cause a dangerously slow heart rate.

Side effects

Common effects include fatigue, cold hands and feet, dizziness and vivid dreams.

Stop and seek urgent medical care for:

• A heart rate below 50 beats per minute, or fainting.
• Severe dizziness, confusion, or signs of very low blood pressure.
• New or worsening shortness of breath, swelling in the legs, or sudden weight gain, which can signal worsening heart failure.

Safety essentials

• Never stop metoprolol suddenly, even to switch to a different medicine. Your prescriber will taper the dose over 1 to 2 weeks to avoid rebound high blood pressure, chest pain or a heart attack.
• Check your pulse periodically and tell your doctor if it consistently falls below 50 beats per minute or you feel unusually faint.
• Tell any surgical or anesthesia team that you take metoprolol before an operation, since anesthetic drugs can interact with beta-blockers.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.