DILTIAZEM (Cardizem)



Classification: calcium channel blocker
  • prolongs the refractory periods of the AV node and intranodal conduction
  • provides temporary control of rapid ventricular rate in atrial fibrillation and atrial flutter, but rarely converts to normal sinus rhythm
  • may provide rapid conversion of paroxysmal supraventricular tachycardias to sinus rhythm
  • has been used as intracoronary injection to prevent vasospasm during coronary angioplasty
  • used post radial artery coronary bypass graphs to prevent spasm
  • Bolus:
    • 0.1-0.3mg/kg IV direct over 2 minutes
    • a subsequent dose of 0.35mg/kg may be administered after 15 minutes if the initial response is inadequate
  • Infusion:
    • 5-10 mg/h immediately following direct injection
    • may be increased by 5 mg/h to a maximum of 15mg/h to achieve target
  • Intracoronary
    • 1 mg

IV Infusion: 
dilute 125 mg in 100ml dextrose 5% or sodium chloride 0.9% (1 mg/ml)

  • refrigerate unused vial
Adverse Effects:
  • hypotension, decreased SVRI
  • decreased cardiac output
  • arrhythmias
  • bradycardia
  • AV block
  • prolonged QT 
  • flushing
  • dizziness
  • dyspnea
  • headache
  • contraindicated in patients with hypotension, sick sinus syndrome, second and complete AV block, and in patients with acute myocardial infarction and pulmonary edema
  • use cautiously in patients with AV conduction delays or transient sinus pauses
Drug Interactions:
  • diltiazem + beta blockers = decreased HR, CI and prolonged PR interval
  • diltiazem + digoxin = increased digoxin plasma concentrations
  • diltiazem + cyclosporin = increased cyclosporin plasma concentrations
  • diltiazem + amiodardone = increased diltiazem plasma concentrations
  • diltiazem + cisapride = prolonged QT with Torsades de Pointes
Monitoring Therapy:
  • continuous heart rate and rhythm
  • PR interval and QT interval
  • blood pressure
  • urine output
  • central or mixed venous oxygen saturation
  • lacate
  • breath sounds
Adult Critical Care Protocol:
  • May be administered IV direct or by IV infusion by an approved nurse in CCTC.
  • Continuous infusion must be administered via an infusion pump.
  • Patient requires placement of an arterial line to monitor BP if intravenous infusion is used.


Lynne Kelly, Pharmacist, CCTC
Brenda Morgan, Clinical Nurse Specialist, CCTC
Last Update: September 19, 2018