Should diltiazem (Cardizem) be stopped?

Should Diltiazem (Cardizem) Be Stopped?

Yes, diltiazem (Cardizem) should be stopped immediately in patients with left ventricular dysfunction (LVEF <40%), decompensated heart failure, AV block greater than first degree, sick sinus syndrome, cardiogenic shock, or pre-excitation syndromes as it is contraindicated in these conditions. 1

Contraindications for Diltiazem Use

Diltiazem must be discontinued in the following situations:

1. Left ventricular dysfunction (LVEF <40%) - Non-dihydropyridine calcium channel blockers like diltiazem can have a detrimental effect on mortality in these patients 1

2. Decompensated heart failure - Diltiazem has negative inotropic effects that can worsen heart failure 1

3. Advanced AV block - Diltiazem can further impair cardiac conduction 1

4. Sick sinus syndrome (without pacemaker) - Can worsen bradycardia 1

5. Cardiogenic shock - Can worsen hypotension 1

6. Pre-excitation syndromes (e.g., Wolff-Parkinson-White) - Can lead to dangerous arrhythmias 1

7. Concomitant use with beta-blockers - This combination significantly increases the risk of bradycardia and heart block 1

Monitoring and Management When Stopping Diltiazem

When discontinuing diltiazem:

• Monitor cardiac rhythm continuously for potential rebound tachycardia
• Monitor blood pressure for potential changes
• Consider alternative therapies based on the original indication:
  • For rate control in atrial fibrillation with LV dysfunction: beta-blockers or digoxin 1
  • For hypertension with LV dysfunction: ACE inhibitors, ARBs, or dihydropyridine calcium channel blockers 1
  • For angina with LV dysfunction: nitrates and beta-blockers 1

Specific Scenarios Requiring Diltiazem Discontinuation

1. Sodium Channel Blocker Toxicity

If a patient is taking sodium channel blockers and presents with atrial flutter with 1:1 AV conduction, diltiazem should be withdrawn 2

2. Hypotension

Diltiazem can cause significant hypotension requiring discontinuation in up to 30% of critically ill patients 3. If systolic blood pressure drops below 90 mmHg or the patient shows signs of hypoperfusion, the drug should be stopped.

3. Torsades de Pointes Risk

In patients with risk factors for QT prolongation and torsades de pointes (see Table 10 in 2), diltiazem should be used with extreme caution or discontinued.

Alternative Management Strategies

For patients requiring rate control after diltiazem discontinuation:

1. For SVT management: Consider synchronized cardioversion for hemodynamically unstable patients 2

2. For long-term management: Consider catheter ablation for definitive treatment of recurrent SVT, with success rates exceeding 95% for AVNRT 1

3. For acute management: Intravenous beta-blockers may be reasonable for acute treatment in hemodynamically stable patients with SVT 2

Key Pitfalls to Avoid

• Don't abruptly discontinue without a plan for alternative rate control if needed
• Don't miss the diagnosis of LV dysfunction where diltiazem is contraindicated
• Don't combine diltiazem with beta-blockers without careful monitoring for bradycardia and heart block
• Don't restart diltiazem in patients who previously experienced hypotension with its use

In summary, diltiazem should be stopped in patients with contraindications or who develop adverse effects from the medication. Alternative therapies should be selected based on the patient's underlying condition and hemodynamic status.