Stopping Cardizem 5mg/hr Infusion
Do not abruptly stop Cardizem (diltiazem) 5mg/hr infusion without first assessing the clinical indication, hemodynamic stability, and having a transition plan in place—IV diltiazem infusions are intended for short-term rate control (up to 24 hours maximum) and require either transition to oral therapy or careful discontinuation based on the underlying arrhythmia. 1
Understanding Your Current Therapy
- You are receiving a continuous IV infusion of diltiazem at 5 mg/hr, which is the lowest maintenance infusion rate studied and approved by the FDA 1
- IV diltiazem infusions are specifically designed for temporary heart rate control in atrial fibrillation or atrial flutter, not for long-term management 2, 1
- The FDA explicitly states that infusion duration exceeding 24 hours is not recommended due to dose-dependent, non-linear pharmacokinetics 1
Critical Decision Points Before Stopping
Assess Your Clinical Indication
- If prescribed for atrial fibrillation/flutter rate control: You need ongoing rate control therapy—stopping without transition to oral medication will likely result in recurrent rapid heart rate 2, 3
- If prescribed for supraventricular tachycardia (SVT): Once the acute episode is controlled, the infusion can be discontinued if rhythm has converted to normal sinus rhythm 4
- If prescribed for hypertension or angina: IV diltiazem is not the appropriate route—you should already be on or transitioning to oral formulations 3
Check Your Current Hemodynamic Status
- Blood pressure: If you have symptomatic hypotension (dizziness, lightheadedness when standing, confusion), the infusion should be reduced or stopped 3, 5
- Heart rate: If your heart rate is excessively slow (bradycardia), particularly below 50-60 bpm with symptoms, discontinuation may be necessary 2, 3
- Signs of heart failure: New or worsening shortness of breath, weight gain, or edema suggests the medication may be causing harm and requires immediate reassessment 3
Safe Discontinuation Algorithm
If Stopping is Appropriate (Rhythm Converted or Adverse Effects)
- Discontinue the infusion if you have achieved stable normal sinus rhythm after SVT treatment 4
- Discontinue immediately if severe hypotension requiring intervention has developed (this occurred in 30% of patients on diltiazem in one critical care study) 5
- Discontinue immediately if severe bradycardia or heart block develops 2, 4
If Ongoing Rate Control is Still Needed
- Transition to oral diltiazem before stopping the IV infusion to maintain therapeutic effect 3, 1
- Start with 120 mg daily of long-acting oral formulation (extended-release or controlled-delivery), which can be titrated up to 360 mg daily as needed 3, 4
- Overlap therapy: Begin oral diltiazem while continuing the IV infusion, then discontinue IV after the first oral dose has been absorbed (typically 2-4 hours for sustained-release formulations) 3
Critical Contraindications to Continuing Diltiazem (Any Form)
- Second or third-degree AV block without a functioning pacemaker 2, 3, 4
- Decompensated systolic heart failure or severe left ventricular dysfunction 2, 3, 4
- Wolff-Parkinson-White syndrome with atrial fibrillation/flutter 2, 3, 4
- Cardiogenic shock 3, 1
- Sick sinus syndrome without a pacemaker 3, 4
Common Pitfalls to Avoid
- Do not stop abruptly if you still have atrial fibrillation/flutter—your heart rate will likely become rapid again, potentially causing hemodynamic compromise 2
- Do not continue beyond 24 hours—the FDA has not studied safety or efficacy beyond this timeframe, and dose-dependent pharmacokinetics make prolonged infusions unpredictable 1
- Do not assume asymptomatic low blood pressure requires stopping—a BP of 115/60 mmHg without symptoms is within target range and does not require medication adjustment 3
- Avoid combining with beta-blockers—if you are also on beta-blocker therapy, the risk of severe bradycardia and heart block is significantly increased 3, 4