Is there a medical reason to prescribe both atenolol and metoprolol (beta blockers) concurrently to a patient post coronary artery bypass grafting (CABG)?

From the Guidelines

Taking both atenolol and metoprolol simultaneously is not recommended for patients post coronary artery bypass grafting (CABG) as it increases the risk of adverse effects without providing additional therapeutic benefits. The use of beta-blockers in patients undergoing surgery, including CABG, is guided by recommendations that emphasize the importance of continuing beta-blockers in patients who are already receiving them for conditions such as angina, symptomatic arrhythmias, hypertension, or other Class I guideline indications 1. However, these guidelines do not support the initiation of two beta-blockers concurrently in the perioperative period for patients undergoing CABG.

The rationale behind using a single beta-blocker, such as metoprolol or atenolol, is to reduce the heart's workload, control blood pressure, and prevent complications without unnecessarily increasing the risk of side effects like bradycardia, hypotension, and worsening heart failure. The 2014 ACC/AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery provides a systematic review of perioperative beta-blockade, highlighting the importance of dose titration and the selection of appropriate patients for beta-blocker therapy 1.

Key points to consider include:

• The potential for increased adverse effects with dual beta-blocker therapy without additional benefits.
• The importance of careful patient selection and dose titration for beta-blocker therapy in the perioperative period.
• The need for clear communication and supervision when transitioning between different beta-blockers.

In clinical practice, if a patient is found to be taking both atenolol and metoprolol after CABG, it is crucial to investigate the reason for this regimen, as it may indicate a misunderstanding or oversight in medication reconciliation. The patient or caregiver should be advised to contact their cardiologist or primary care physician to clarify the correct medication regimen and avoid potential harm. The general recommendation is to use a single beta-blocker, as indicated, and to manage the patient's condition based on clinical guidelines and the patient's specific needs.

From the Research

Medical Reasoning for Concurrent Prescription of Atenolol and Metoprolol

There is no direct evidence to support the concurrent prescription of atenolol and metoprolol (beta blockers) to a patient post coronary artery bypass grafting (CABG).

• The provided studies do not specifically address the use of both atenolol and metoprolol in patients post CABG 2, 3, 4, 5, 6.
• Studies have compared the effects of metoprolol and atenolol in patients with hypertension or heart failure, but not in the context of CABG 4, 5, 6.
• One study discussed the potential risks of combining diltiazem and beta-blocker therapy, but did not address the use of two beta blockers concurrently 2.
• Another study provided guidance on switching between beta blockers, but did not discuss the use of multiple beta blockers at the same time 3.

Comparison of Atenolol and Metoprolol

• Some studies have compared the effects of atenolol and metoprolol in patients with hypertension or heart failure, with varying results 4, 5, 6.
• One study found that metoprolol was more effective than atenolol in reducing the risk of combined end-points in patients with mild-to-moderate heart failure 4.
• Another study found that atenolol was more effective than metoprolol in reducing blood pressure and heart rate in hypertensive patients, especially 25 hours after dosing 6.
• However, these studies do not provide evidence to support the concurrent prescription of atenolol and metoprolol in patients post CABG.