What is the administration protocol for Diltiazem (Cardizem)?

From the Guidelines

Cardizem (diltiazem) should be administered intravenously for acute rate control in supraventricular tachycardias or atrial fibrillation with rapid ventricular response, with a standard dosing of an initial bolus of 0.25 mg/kg (typically 15-20 mg) administered over 2 minutes, as recommended by the most recent guidelines 1. The administration protocol for Diltiazem (Cardizem) involves:

• An initial bolus of 0.25 mg/kg (typically 15-20 mg) administered over 2 minutes
• A second bolus of 0.35 mg/kg (typically 20-25 mg) can be given if the response is inadequate after 15 minutes
• A continuous infusion may be started at 5-15 mg/hour, titrated to heart rate response
• For oral administration in chronic management, start with 30 mg four times daily or 60-120 mg twice daily of extended-release formulations, with gradual titration based on response
• Maximum daily dose is typically 360-480 mg The mechanism of action of Cardizem involves blocking calcium channels in cardiac tissue, reducing conduction through the AV node and decreasing myocardial contractility, making it effective for rate control but also explaining its potential side effects including hypotension, bradycardia, and heart block, as noted in the guidelines 1. Key considerations for the use of Cardizem include:
• Use cautiously in patients with heart failure, hypotension, or conduction disorders
• Contraindicated in severe hypotension, cardiogenic shock, sick sinus syndrome without a pacemaker, and second or third-degree AV block
• Monitor for potential side effects, including hypotension, bradycardia, and heart block, as recommended by the guidelines 1.

From the FDA Drug Label

DOSAGE AND ADMINISTRATION Direct Intravenous Single Injections (Bolus) The initial dose of diltiazem hydrochloride injection should be 0. 25 mg/kg actual body weight as a bolus administered over 2 minutes (20 mg is a reasonable dose for the average patient). If response is inadequate, a second dose may be administered after 15 minutes. The second bolus dose of diltiazem hydrochloride injection should be 0. 35 mg/kg actual body weight administered over 2 minutes (25 mg is a reasonable dose for the average patient). Continuous Intravenous Infusion For continued reduction of the heart rate (up to 24 hours) in patients with atrial fibrillation or atrial flutter, an intravenous infusion of diltiazem hydrochloride injection or diltiazem hydrochloride for injection may be administered. The recommended initial infusion rate of diltiazem hydrochloride injection or diltiazem hydrochloride for injection is 10 mg/h.

The administration protocol for Diltiazem (Cardizem) is as follows:

• Initial dose: 0.25 mg/kg actual body weight as a bolus administered over 2 minutes
• Second dose (if needed): 0.35 mg/kg actual body weight administered over 2 minutes, given 15 minutes after the initial dose
• Continuous infusion:
  • Initial rate: 10 mg/h
  • Maximum rate: 15 mg/h
  • Maximum duration: 24 hours 2

From the Research

Administration Protocol for Diltiazem (Cardizem)

• The recommended starting dose of Diltiazem for controlling rapid ventricular response in atrial fibrillation is an intravenous bolus of 0.25 mg/kg over 2 minutes 3.
• However, a lower dose of Diltiazem (≤ 0.2 mg/kg) may be as effective as the standard dose in controlling rapid AF and reduce the risk of hypotension 3.
• In prehospital settings, a protocol-directed dose of 0.25mg/kg (maximum of 20mg) of Diltiazem is used for stable, symptomatic patients in AFIB with RVR at a rate of >150 beats per minute (bpm) with a narrow complex 4.
• For critically ill patients with sinus tachycardia, an intravenous infusion of Diltiazem can be administered as a slow 10-mg bolus dose (0.1-0.2 mg/kg ideal body weight), followed by an infusion started at 5 or 10 mg/hr and increased up to 30 mg/hr, as needed, to decrease heart rate to <100 beats/min 5.
• Appropriate dosing of intravenous Diltiazem is crucial to avoid hypotension, and interventions such as education and medication alerts can improve the percentage of patients receiving appropriate doses 6.

Key Considerations

• The dose of Diltiazem should be adjusted according to the patient's response and tolerance 3, 4, 5.
• Concomitant beta-adrenoceptor antagonist therapy may increase the risk of atrioventricular block 7.
• Diltiazem can be effective in controlling heart rate in patients with contraindications to beta-blockers or in whom beta-blockers are ineffective 5.

Dosing Regimens

• Low-dose Diltiazem (≤ 0.2 mg/kg) may be used to reduce the risk of hypotension 3.
• Standard dose Diltiazem (> 0.2 and ≤ 0.3 mg/kg) is commonly used, but may be associated with a higher risk of hypotension 3.
• High-dose Diltiazem (> 0.3 mg/kg) is not recommended due to the increased risk of hypotension 3.