Can diltiazem (calcium channel blocker) be stopped abruptly?

Abrupt Discontinuation of Diltiazem

Diltiazem can be stopped abruptly without causing a withdrawal syndrome, but caution is warranted in patients with coronary artery disease due to potential risk of rebound ischemia.

Safety of Abrupt Discontinuation

The safety of abrupt diltiazem discontinuation varies by clinical context:

Evidence Supporting Safe Discontinuation

• A retrospective study specifically examining diltiazem withdrawal in patients with Prinzmetal's variant angina found no evidence of rebound anginal symptoms when diltiazem was abruptly discontinued 1
• This study compared angina frequency after abrupt discontinuation of both diltiazem and placebo, finding no significant difference in symptom recurrence between groups
• No significant adverse events such as myocardial infarction or unstable angina occurred after withdrawal of diltiazem

Precautions When Discontinuing Diltiazem

Despite evidence supporting safe discontinuation, certain patient populations require caution:

• Coronary Artery Disease: Patients with unstable angina or non-ST elevation MI may experience symptom recurrence if diltiazem is abruptly stopped 2
• Atrial Fibrillation: In patients using diltiazem for rate control, abrupt discontinuation could lead to rapid ventricular response 3
• Heart Failure: While diltiazem should generally be avoided in patients with severe LV dysfunction, those who are on it should be monitored closely during discontinuation 2

Recommendations for Discontinuation

Based on the available evidence, the following approach is recommended:

1. Patients with Stable Conditions:

   • Diltiazem can be stopped abruptly without tapering in most stable patients
   • Monitor for return of symptoms (hypertension, angina, tachyarrhythmias)

2. High-Risk Patients:

   • Consider gradual tapering in patients with:
     • Unstable angina or recent non-ST elevation MI
     • Poorly controlled atrial fibrillation
     • Variant (Prinzmetal's) angina
   • Have alternative medications ready if symptoms recur

3. Monitoring After Discontinuation:

   • Follow blood pressure and heart rate for several days after discontinuation
   • Be alert for return of original symptoms that diltiazem was treating

Clinical Context Considerations

• Dose and Duration: Higher doses (>240 mg/day) and longer treatment duration may theoretically increase risk of symptom recurrence, though evidence from 1 did not show increased rebound even with higher doses
• Formulation: Extended-release formulations (once-daily) may have a more gradual offset of effect compared to immediate-release formulations 4
• Concomitant Medications: If transitioning to another rate-controlling agent (e.g., beta-blocker), ensure complete clearance of diltiazem before starting the new medication to avoid synergistic effects on AV nodal conduction 3

Conclusion

While diltiazem can generally be discontinued abruptly without a formal withdrawal syndrome, clinical judgment should be exercised based on the indication for therapy and patient risk factors. The primary concern is not withdrawal symptoms but rather recurrence of the condition being treated.