What is the equivalent dose of diltiazem (calcium channel blocker) to Coreg (carvedilol, beta-blocker) 3.125mg twice daily (bid)?

No Direct Equivalent Dose Between Diltiazem and Carvedilol

There is no direct equivalent dose between diltiazem (calcium channel blocker) and carvedilol (beta-blocker) as they are different medication classes with distinct mechanisms of action.

Fundamental Differences Between These Medications

Mechanism of Action

• Carvedilol (Coreg): A non-selective beta-blocker that also has alpha-1 blocking properties
• Diltiazem: A non-dihydropyridine calcium channel blocker that blocks calcium influx into cardiac and smooth muscle cells

These medications work through completely different pathways to affect heart rate and blood pressure, making direct dose equivalence impossible.

Clinical Considerations When Switching Between These Medications

If a patient needs to be switched from carvedilol to diltiazem, the following approach should be used:

Starting Diltiazem Dosing

• Initial diltiazem dose: 120 mg daily in divided doses 1
• Titrate based on clinical response to 120-360 mg daily in divided doses 1
• For extended-release formulations: Start with equivalent daily dose given once daily

Monitoring Parameters

• Heart rate
• Blood pressure
• Signs of fluid retention
• Symptoms of heart failure (if applicable)

Important Clinical Warnings

• Do not administer both medications simultaneously at full doses due to risk of profound bradycardia, heart block, and hypotension 1
• Avoid abrupt discontinuation of carvedilol as this can lead to rebound hypertension or worsening angina 1
• Use extreme caution in patients with:
  • Heart failure (diltiazem may worsen heart failure in patients with LV dysfunction) 1
  • Pre-excited atrial fibrillation (diltiazem can accelerate ventricular response) 1
  • Conduction disorders (both drugs can worsen AV block) 1

Clinical Context Considerations

• If treating hypertension: Diltiazem 120-360 mg daily is typically effective 1
• If treating angina: Higher doses of diltiazem (up to 480 mg/day) may be needed 1
• If treating atrial fibrillation for rate control: Diltiazem 120-360 mg daily in divided doses 1

Transition Strategy

1. Start diltiazem at low dose (120 mg daily in divided doses)
2. Monitor patient response for 2-4 days
3. Begin tapering carvedilol while increasing diltiazem as needed
4. Complete transition over 1-2 weeks to avoid rebound effects

Remember that these medications have different side effect profiles and contraindications that must be considered when making this switch.