What is the equivalent dosing when converting metoprolol (beta-blocker) to carvedilol (beta-blocker)?

From the Guidelines

When converting from metoprolol to carvedilol, the general equivalent dosing ratio is approximately 5:1, with a recommended starting dose of carvedilol 6.25 mg twice daily for metoprolol tartrate 50 mg twice daily, and titrating upward as tolerated, monitoring for side effects such as dizziness, hypotension, and bradycardia, as evidenced by the Carvedilol or Metoprolol European Trial (COMET) which demonstrated a 17% greater mortality reduction in favor of carvedilol compared with metoprolol tartrate 1. The dosing ratio is not 1:1 due to the difference in receptor activity between carvedilol, a non-selective beta-blocker with additional alpha-blocking properties, and metoprolol, a selective beta-1 blocker.

• For metoprolol tartrate 25 mg twice daily, the equivalent carvedilol dose would be 3.125 mg twice daily.
• For metoprolol tartrate 50 mg twice daily, use carvedilol 6.25 mg twice daily.
• For metoprolol tartrate 100 mg twice daily, convert to carvedilol 12.5 mg twice daily.
• For metoprolol tartrate 200 mg twice daily, use carvedilol 25 mg twice daily. It is essential to start with a lower dose of carvedilol and titrate upward as tolerated, monitoring for side effects, particularly in patients with heart failure, as the alpha-blocking effects of carvedilol may cause additional vasodilation and potential hypotension initially, as shown in the Multicenter Oral Carvedilol Heart Failure Assessment (MOCHA) trial which demonstrated that the effect of carvedilol is dose-related, with higher doses showing greater LV functional and clinical superiority 1.

From the Research

Equivalent Dosing for Metoprolol and Carvedilol

When converting metoprolol to carvedilol, the equivalent dosing is not directly stated in the provided studies. However, some studies provide information on the dosing of metoprolol and carvedilol in various clinical settings:

• The study 2 compared carvedilol with metoprolol succinate in patients with stable chronic heart failure, but it did not provide a direct conversion ratio between the two medications.
• The study 3 compared metoprolol with carvedilol in patients after acute myocardial infarction, and it reported that the mean doses for metoprolol and carvedilol did not significantly differ (37.2 ± 27.8% and 35.8 ± 31.0%, respectively), but it did not provide a clear conversion ratio.
• The study 4 discussed the rationale and practical considerations for switching between beta blockers in heart failure patients, including carvedilol and metoprolol, but it did not provide a specific conversion ratio.

Key Considerations for Converting Metoprolol to Carvedilol

Some key considerations when converting metoprolol to carvedilol include:

• The pharmacological properties of the two medications, such as receptor subtype blockade and ancillary properties 4
• The clinical benefits and safety profiles of the two medications in specific patient populations, such as those with heart failure or after acute myocardial infarction 2, 3
• The need for individualized dose adjustment and monitoring when switching between beta blockers 4, 5

Dosing Recommendations

While there is no direct conversion ratio provided in the studies, the following dosing information may be useful:

• Metoprolol: typically dosed at 200 mg/day in clinical trials 3
• Carvedilol: typically dosed at 50 mg/day in clinical trials 3
• When switching between carvedilol and metoprolol, the dose of the new medication may need to be adjusted based on the patient's clinical response and tolerance 4, 5