Carvedilol vs. Metoprolol: Which Is Better for Blocking Heart Failure?

Carvedilol and metoprolol are both beta-blocker medications, which are a class of drugs used to treat various cardiovascular conditions like heart failure and hypertension (high blood pressure). These medications are similar but have some differences in their list of indications, and one may be a better choice for some individuals.

Main Similarities and Differences 

What Is Carvedilol?

Carvedilol is a non-selective beta-blocker that works by blocking beta-1 receptors located in the heart and beta-2 receptors in the blood vessels and lungs. This blocks the actions of chemicals that occur naturally in your body, like epinephrine, resulting in lower blood pressure, decreased heart rate, and less overall strain on the heart.

Carvedilol is taken by mouth and is available in immediate-release tablets, which are taken two to three times daily, and extended-release tablets, which are taken just once daily.

Indications for carvedilol include:

• Mild to severe chronic heart failure
• Left ventricular dysfunction following myocardial infarction, or heart attack, in clinically stable individuals
• Hypertension or high blood pressure

Benefits of Carvedilol

Some benefits of carvedilol include:

• Since it has alpha-blocking effects (the ability to block alpha receptors in addition to beta receptors), it helps relax blood vessels, improving blood flow, which can improve blood pressure and heart function
• It can help prevent further damage after a heart attack by improving the heart’s efficiency and reducing the amount of oxygen it demands

Side Effects of Carvedilol

Common side effects of carvedilol include:

• Dizziness or lightheadedness, especially when going from a seated to a standing position quickly
• Fatigue or tiredness, as beta-blockers can slow your heart rate and contribute to overall lower energy levels
• Hypotension, or low blood pressure
• Bradycardia, or slow heart rate
• Shortness of breath, which is usually mild and temporary

Less common side effects of carvedilol that may be more serious include:

• Worsening heart failure, including symptoms like shortness of breath or edema (swelling), most commonly in the feet, ankles, or legs
• Asthma or bronchospasm, as beta-2 receptors are located in the lungs and can be targeted by carvedilol as well, resulting in airway narrowing
• Liver issues, which may be accompanied by yellowing of the skin or eyes (jaundice), dark urine, or extreme fatigue
• Hyperglycemia, or high blood sugar

What Is Metoprolol?

Metoprolol is a cardioselective beta-blocker, which means it has more affinity to block beta-1 receptors primarily located in the heart and has minimal effect on beta-2 receptors in the lungs and blood vessels.

Approved indications for metoprolol include:

• Hypertension, or high blood pressure.
• Angina pectoris
• Myocardial infarction, or following a heart attack, to lower the risk of heart-related death

Benefits of Metoprolol

Benefits of metoprolol include:

• It is preferred in people with lung conditions like asthma or COPD because it has minimal effect compared to nonselective beta-blockers like carvedilol
• Available in more formulations compared to carvedilol, including immediate-release tablets, extended-release tablets, and intravenous injection

Side Effects of Metoprolol

Common side effects of metoprolol are similar to those of carvedilol and include the following:

• Dizziness or lightheadedness, especially when going from a seated to a standing position quickly
• Fatigue or tiredness
• Hypotension
• Bradycardia
• Shortness of breath
• Cold hands or feet due to reduced blood flow to these extremities

Potentially more serious side effects, again similar to those of carvedilol, include:

• Worsening heart failure 
• Depression or mood changes
• Sleep disturbances such as insomnia, vivid dreams or nightmares
• Gastrointestinal issues like nausea, vomiting, diarrhea or constipation
• Sexual side effects such as lowered sex drive or erectile dysfunction in men

Risks of Carvedilol and Metoprolol

These drugs have a number of important precautions to be aware of. Take carvedilol or metoprolol exactly as prescribed to you, and do not stop taking the medication abruptly.

If you forget to take a dose of carvedilol or metoprolol, you can take it as soon as you remember. If you are closer to your next dose than the dose you missed, go ahead and skip the missed dose and wait for your next scheduled one. For example, if you normally take carvedilol twice daily at 8 am and 8 pm, and you remember at 5 pm that you forgot your morning dose, just wait and take your next dose that night at 8 pm. Do not double up doses to make up for missed ones.

Interactions

Some important interactions exist between beta-blockers and other medications:

• Calcium channel blockers like Norvasc (amlodipine) or Cardizem (diltiazem)
• Diabetes medications, like Glucotrol (glipizide), Jardiance (empagliflozin), and Tradjenta (linagliptin)
• NSAIDs (nonsteroidal anti-inflammatory drugs) such as Motrin (ibuprofen) or Celebrex (celecoxib) can lower the effectiveness of beta-blockers
• Some antiarrhythmic drugs, such as Cordarone (amiodarone) or digoxin

Withdrawal

If you stop taking a beta-blocker like carvedilol or metoprolol abruptly, you may experience serious side effects such as rebound hypertension, angina (chest pain), or increased risk of a heart attack, particularly if you have coronary artery disease.

If you need to stop taking carvedilol or metoprolol, you should be gradually tapered off the medication under your healthcare provider’s supervision.

Who Should Be Cautious When Taking Carvedilol or Metoprolol?

Beta-blockers are not appropriate for everyone, and there are some groups of people who should be cautious when taking them.

• People with diabetes because these medications can mask the symptoms of low blood sugar like shakiness or fast heartbeat.
• People with arrhythmias or heart block because beta-blockers can slow the heart rate, which may worsen some types of arrhythmias.
• People with asthma, COPD, or other lung issues that may be worsened by the targeting of beta-2 receptors by non-selective beta-blockers like carvedilol would likely be better suited for selective beta-blockers like metoprolol or atenolol.
• People who drink alcohol should use caution when also taking beta-blockers, as this combination can increase hypotensive (blood pressure-lowering) effects and increase the risk of dizziness or fainting.

Summary

Carvedilol and metoprolol are beta-blocker medications that have important indications for heart conditions. Both can lower your heart rate and make your heart work more efficiently. They have similar side effects, such as fatigue, dizziness upon standing, and shortness of breath. 

The most important difference between the two medications is their selectivity, or which type of beta receptors they are likely to attach to. Carvedilol is non-selective, so it will affect both the heart and lungs, whereas cardioselective metoprolol is more likely to affect primarily the heart, with lesser lung effects. Those with asthma or other lung conditions are more likely suited for metoprolol over carvedilol.