Metoprolol Succinate to Carvedilol Dose Conversion in Heart Failure
When converting from metoprolol succinate to carvedilol in heart failure patients, a metoprolol succinate dose of 200 mg once daily is approximately equivalent to carvedilol 25 mg twice daily (50 mg total daily dose). 1
Conversion Rationale and Evidence
The 2022 ACC/AHA/HFSA Heart Failure Guidelines provide clear target doses for both medications in heart failure with reduced ejection fraction (HFrEF):
- Metoprolol succinate: Target dose of 200 mg once daily
- Carvedilol: Target dose of 25-50 mg twice daily 1
This conversion ratio is supported by clinical trials where these doses were established as the target doses that demonstrated mortality benefit in heart failure patients.
Detailed Conversion Table
| Metoprolol Succinate Dose | Carvedilol Equivalent Dose |
|---|---|
| 25 mg once daily | 3.125 mg twice daily |
| 50 mg once daily | 6.25 mg twice daily |
| 100 mg once daily | 12.5 mg twice daily |
| 200 mg once daily | 25 mg twice daily |
Conversion Process
Initial Assessment:
- Check current heart rate, blood pressure, and symptoms
- Review current metoprolol succinate dose and patient tolerance
Conversion Strategy:
- Discontinue metoprolol succinate
- Start carvedilol at the appropriate equivalent dose based on the table above
- Begin with a lower dose if the patient has:
- Systolic BP <100 mmHg
- Heart rate <60 bpm
- Signs of fluid retention or worsening heart failure
Titration Schedule:
Important Considerations
Pharmacological Differences
Carvedilol differs from metoprolol succinate in several ways:
- Carvedilol is non-selective (blocks β1, β2, and α1 receptors)
- Metoprolol succinate is β1-selective at lower doses but becomes less selective at higher doses 3
- Carvedilol has additional vasodilatory and antioxidant properties
Clinical Outcomes
The COMET trial demonstrated that carvedilol extended survival compared to metoprolol tartrate (not succinate) in heart failure patients, with all-cause mortality of 34% for carvedilol versus 40% for metoprolol tartrate (HR 0.83, p=0.0017) 4. However, it's important to note this study used metoprolol tartrate, not the extended-release succinate formulation commonly used today.
Monitoring During Conversion
Monitor for:
- Bradycardia (heart rate <50 bpm)
- Hypotension (systolic BP <90 mmHg)
- Worsening heart failure symptoms
- Fluid retention
Contraindications
Avoid beta-blockers including carvedilol in patients with:
- Second or third-degree heart block without a pacemaker
- Severe bradycardia (<50 bpm)
- Cardiogenic shock
- Decompensated heart failure requiring inotropic support
- Severe bronchial asthma or COPD with bronchospasm 1, 2
Conclusion
When converting from metoprolol succinate to carvedilol, use the established equivalent doses, start at an appropriate dose based on the patient's current metoprolol dose, and titrate gradually while monitoring for adverse effects. The target dose of carvedilol (25-50 mg twice daily) has been shown to provide mortality benefits in heart failure patients comparable to metoprolol succinate 200 mg daily.