Drug Summary

Diltiazem (Cardizem®)

Pharmacologic properties:

Diltiazem is a calcium channel blocking agent that inhibits the influx of calcium ions during membrane depolarization of cardiac and vascular smooth muscle. It’s action is to slow AV nodal conduction and increase the AV nodal refractory period. Diltiazem slows the ventricular rate in patients with a rapid ventricular response during atrial fibrillation or atrial flutter, potentially converts supraventricular tachycardia to normal sinus rhythm, and decreases total peripheral resistance in both systolic and diastolic blood pressure.


  • Narrow complex atrial fibrillation/flutter with rapid ventricular rate (>150 bpm)
  • PSVT refractory to adenosine


  • Patients with pulmonary edema or severe heart failure/cardiogenic shock
  • Complete heart block
  • Hypotension (SBP <90) or cardiogenic shock
  • Recently (within past 1 hour) received IV ß-blocker
  • Patients with a history of Wolff-Parkinson-White Syndrome (WPW)
  • Sick sinus syndrome
  • Ventricular tachycardia or wide complex tachycardia


  • Cautious use in patients with congestive heart failure, monitor for signs of pulmonary edema
  • Cautious use in patients who are already taking antihypertensive medications, monitor for hypotension

Adverse Reactions:

  • Hypotension
  • Bradycardia
  • Heart block

Dosage and administration:

  • Adult
    • 0.25 mg/kg slow IV bolus (maximum dose 20 mg)
  • Pediatric
    • Not Indicated