II. Indications

  1. Hypertension
    1. Consider Dihydropyridine Calcium Channel Blocker (e.g. Amlodipine) instead if Heart Rate control is not needed
  2. Atrial Fibrillation with Rapid Ventricular Response
    1. Highly effective at controlling ventricular rate
  3. Paroxysmal Supraventricular Tachycardia
    1. Less studied than Verapamil for PSVT
  4. Supraventricular Tachycardia
    1. Terminates AV Node reentry Tachycardias

III. Contraindications

  1. Wolff-Parkinson-White Syndrome with Atrial Fibrillation
    1. Paroxysmal accelerated ventricular response
    2. Risk of progression into Ventricular Fibrillation
  2. Wide Complex Tachycardia (unless supraventricular)
    1. Risk of severe Hypotension
    2. May progress into Ventricular Fibrillation
  3. Sinus Node or AV Node dysfunction without Pacemaker
    1. AV Block
    2. Sick Sinus Syndrome
  4. Severe Congestive Heart Failure
  5. Concurrent Intravenous Beta Blocker use

IV. Mechanism

  1. See Calcium Channel Blocker
  2. General
    1. Non-Dihydropyridines are active at cardiac and vascular Smooth Muscle
    2. Contrast with Dihydropyridines which are primarily active only at vascular Smooth Muscle
    3. Calcium Channel Blockers decrease Smooth MuscleCalcium influx resulting in vascular Smooth Muscle relaxation
  3. AV Node effects
    1. Slow AV Node Conduction
    2. Prolong AV Node refractory period
  4. Less negative hemodynamic effects for Diltiazem than Verapamil
    1. Potent negative chronotropic effect
    2. Minimal negative inotropic effect
    3. Diltiazem effects Left Ventricular Dysfunction less
  5. Coronary vasodilatation

V. Medications

  1. Diltiazem
    1. Preferred of Non-Dihydropyridine class
  2. Verapamil
  3. Bepridil

VI. Adverse Effects

VII. Drug Interactions

VIII. References

  1. (2022) Presc Lett 29(11): 64-5

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