Can atenolol (beta-blocker) be discontinued and metoprolol (beta-blocker) be started in its place?

Switching from Atenolol to Metoprolol

Yes, atenolol can be safely discontinued and replaced with metoprolol, but this switch should follow a structured approach to avoid cardiovascular risks. 1, 2

Rationale for Switching

• Metoprolol (particularly metoprolol succinate) is preferred over atenolol for heart failure patients as it is one of the three beta-blockers proven to reduce mortality, along with bisoprolol and carvedilol 1
• Atenolol should be avoided in patients with hypertension who are pregnant or planning pregnancy due to its association with lower birth weight 1
• Metoprolol has better evidence for cardiovascular outcomes compared to atenolol, which is specifically mentioned as not preferred in heart failure 1

Switching Protocol

Step 1: Assessment Before Switch

• Evaluate current heart rate, blood pressure, and symptoms of heart failure or cardiovascular disease 1, 2
• Check for contraindications to metoprolol including severe bradycardia, heart block, cardiogenic shock, or active asthma 2

Step 2: Initiation of Metoprolol

• Start metoprolol while gradually tapering atenolol over 1-2 weeks 2
• For metoprolol tartrate: Begin with 25-50 mg twice daily 2, 3
• For metoprolol succinate (extended-release): Begin with 50 mg once daily 2

Step 3: Tapering Atenolol

• Reduce atenolol dose by 25-50% every 1-2 weeks while increasing metoprolol 2
• Complete overlap approach is preferred to avoid rebound effects 4
• Never stop atenolol abruptly as this can cause rebound hypertension or worsening angina 1, 5

Step 4: Monitoring During Transition

• Monitor blood pressure and heart rate closely during the transition period 2
• Watch for signs of worsening heart failure, including fluid retention or increased fatigue 1
• Target heart rate of 50-60 beats per minute unless limiting side effects occur 2

Dosing Equivalence

• 50 mg atenolol once daily is approximately equivalent to 100 mg metoprolol tartrate (standard release) in antihypertensive effect 3, 6
• Metoprolol tartrate may require twice-daily dosing for optimal 24-hour coverage, while metoprolol succinate provides effective once-daily dosing 7

Special Considerations

• If patient has heart failure, the preferred beta-blockers are bisoprolol, carvedilol, or metoprolol succinate (not metoprolol tartrate) 1
• If marked fatigue or bradycardia occurs during transition, temporarily reduce the dose of the beta-blocker and review the patient in 1-2 weeks 1
• If heart rate drops below 50 bpm with worsening symptoms, halve the dose of beta-blocker 1
• For patients with symptomatic hypotension during transition, consider reducing doses of other vasodilators or diuretics first 1

Important Cautions

• Beta-blockers should never be stopped suddenly unless absolutely necessary due to risk of rebound ischemia, infarction, or arrhythmias 1
• If serious deterioration occurs during transition, seek specialist advice 1
• Patients with severe heart failure (NYHA Class III/IV) should be referred for specialist care during beta-blocker transitions 1