Converting Carvedilol 12.5 mg BID to Bisoprolol
Switch carvedilol 12.5 mg twice daily to bisoprolol 2.5 mg once daily, then titrate upward every 2 weeks as tolerated toward the target dose of 10 mg daily.
Conversion Rationale and Evidence
The ACC/AHA guidelines establish that carvedilol 12.5 mg twice daily (25 mg total daily dose) represents approximately 25-50% of the target dose for heart failure (target: 25-50 mg twice daily) 1. For bisoprolol, the equivalent starting point after conversion is 2.5 mg once daily, which represents 25% of the target dose of 10 mg daily 1, 2.
There is no direct mathematical conversion ratio between carvedilol and bisoprolol because they have different pharmacologic properties—carvedilol provides combined alpha-1 and beta-blockade while bisoprolol is a selective beta-1 blocker 3, 4. The conversion strategy focuses on maintaining beta-blockade while avoiding adverse effects 2.
Step-by-Step Conversion Protocol
Initial Conversion
- Stop carvedilol 12.5 mg twice daily and start bisoprolol 2.5 mg once daily 2, 5
- This conservative starting dose minimizes risk of hypotension or bradycardia during the transition 5
- Clinical evidence demonstrates that switching from carvedilol to bisoprolol at this dose successfully relieves dizziness and hypotension in 56-100% of patients 5
Titration Schedule
Double the bisoprolol dose every 2 weeks as tolerated, following this progression 2:
- Week 0-2: Bisoprolol 2.5 mg once daily
- Week 2-4: Bisoprolol 5 mg once daily
- Week 4+: Bisoprolol 10 mg once daily (target dose)
The target dose of 10 mg daily achieved a 34% relative risk reduction in mortality in the CIBIS-II trial 2
Monitoring Parameters During Conversion
- Check heart rate and blood pressure at each visit during titration 2
- Hold or reduce dose if 2:
- Heart rate <50 bpm with worsening symptoms
- Systolic blood pressure <100 mmHg with symptoms (dizziness, lightheadedness)
- Signs of worsening heart failure (increased dyspnea, weight gain >1.5-2 kg over 2 days, peripheral edema)
Clinical Benefits of Switching
Research demonstrates that switching from carvedilol to bisoprolol in patients experiencing adverse effects allows 5:
- 100% resolution of dizziness in affected patients
- 56% resolution of hypotension (systolic BP <90 mmHg)
- Successful dose escalation from mean 1.84 mg to 3.13 mg over 6 months
- Improved left ventricular ejection fraction and exercise tolerance at 6-month follow-up
The once-daily dosing of bisoprolol also improves medication adherence compared to twice-daily carvedilol 6.
Critical Warnings
Never abruptly discontinue carvedilol without starting bisoprolol, as this risks rebound myocardial ischemia, infarction, and ventricular arrhythmias with up to 50% mortality in some studies 2. The direct switch from carvedilol to bisoprolol maintains continuous beta-blockade 5.
Special Considerations
- If target dose cannot be achieved, maintain the highest tolerated dose—some beta-blocker is better than no beta-blocker, with mortality benefits demonstrated even at 50% of target dose (bisoprolol 5 mg daily) 2
- For worsening congestion during titration, first double the diuretic dose before reducing bisoprolol 2
- Only bisoprolol, carvedilol, and metoprolol succinate have proven mortality reduction in heart failure—this is not a class effect of all beta-blockers 2