What is the conversion dose from 50mg of metoprolol (Lopressor) to carvedilol (Coreg)?

Metoprolol to Carvedilol Conversion

When converting from metoprolol 50 mg to carvedilol, the equivalent dose is 12.5 mg of carvedilol twice daily (25 mg total daily dose). 1

Conversion Rationale

The conversion from metoprolol to carvedilol should follow these principles:

• Metoprolol 50 mg (either as immediate release twice daily or extended-release once daily) is approximately equivalent to carvedilol 12.5 mg twice daily in terms of beta-blocking effects 1
• According to the ACC/AHA guidelines, the target dose for carvedilol in heart failure is 25 mg twice daily, while metoprolol succinate's target dose is 200 mg once daily 1

Conversion Process

1. Initial dose: Start with carvedilol 3.125 mg twice daily 1, 2
2. Titration schedule:
   • Increase dose every 2 weeks if tolerated
   • Titration steps: 3.125 mg → 6.25 mg → 12.5 mg → 25 mg (all doses given twice daily) 1, 2
3. Target dose: 25 mg twice daily, though 12.5 mg twice daily is often sufficient when converting from metoprolol 50 mg 1

Monitoring During Conversion

• Monitor for hypotension, bradycardia, and signs of heart failure during the transition
• Check vital signs at each dose increase
• Be alert for fluid retention which may occur during beta-blocker initiation or dose changes

Important Considerations

• Pharmacological differences: Carvedilol is a non-selective beta-blocker with additional alpha-1 blocking properties, while metoprolol is a selective beta-1 blocker 3
• Blood pressure effects: Carvedilol typically produces a greater reduction in blood pressure than metoprolol due to its alpha-blocking properties 4
• Never abruptly discontinue metoprolol before starting carvedilol - overlap the medications during transition

Special Situations

• Heart failure patients: Start with a lower dose (3.125 mg twice daily) and titrate more slowly 1
• Post-MI patients: Consider starting at 6.25 mg twice daily and titrating to 25 mg twice daily 2
• Hepatic impairment: Carvedilol is contraindicated in severe hepatic impairment 2

Clinical Evidence Supporting Conversion

The COMET trial demonstrated that carvedilol 25 mg twice daily reduced mortality compared to metoprolol tartrate 50 mg twice daily in heart failure patients 5, though both medications produced similar effects on 24-hour heart rate control 6.

Practical Tips

• Take carvedilol with food to reduce orthostatic effects 2
• If the patient experiences side effects during conversion, temporarily return to the previous well-tolerated dose before attempting to increase again
• Ensure the patient understands that carvedilol is taken twice daily, which may differ from their metoprolol regimen if they were on the extended-release formulation