What is the dosing protocol for diltiazem (calcium channel blocker) in managing supraventricular tachycardia or controlling ventricular rate in atrial fibrillation?

From the Guidelines

Diltiazem should be titrated to heart rate, starting with an initial IV bolus of 15-20 mg (0.25 mg/kg) over 2 minutes, followed by an additional 20-25 mg (0.35 mg/kg) if needed, and then maintained at 5-15 mg/hour IV infusion, as recommended by the 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care 1. The dosing protocol for diltiazem in managing supraventricular tachycardia or controlling ventricular rate in atrial fibrillation is based on the patient's response to the initial dose.

• The initial dose is 15-20 mg (0.25 mg/kg) IV bolus over 2 minutes.
• If the response is inadequate after 15 minutes, an additional 20-25 mg (0.35 mg/kg) can be given.
• Once rate control is achieved, the patient can be transitioned to a continuous IV infusion at 5-15 mg/hour, titrating based on heart rate response, as stated in the guidelines 1. Key considerations when using diltiazem include:
• Monitoring blood pressure closely during administration, as hypotension is a common side effect.
• Watching for bradycardia, heart block, and worsening heart failure, particularly in patients with left ventricular dysfunction.
• Using caution in patients with heart failure, hypotension, or those taking beta-blockers due to potential additive effects on cardiac function, as noted in the guidelines 1 and supported by other studies 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). 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. Some patients may maintain response to an initial rate of 5 mg/h The infusion rate may be increased in 5 mg/h increments up to 15 mg/h as needed, if further reduction in heart rate is required.

The dosing protocol for diltiazem in managing supraventricular tachycardia or controlling ventricular rate in atrial fibrillation is as follows:

• Initial dose: 0.25 mg/kg actual body weight as a bolus administered over 2 minutes
• Continuous infusion: initial rate of 10 mg/h, which may be increased in 5 mg/h increments up to 15 mg/h as needed
• Maximum infusion rate: 15 mg/h
• Maximum infusion duration: 24 hours 2

From the Research

Dosing Protocol for Diltiazem

• The dosing protocol for diltiazem in managing supraventricular tachycardia or controlling ventricular rate in atrial fibrillation involves an initial bolus dose followed by a maintenance infusion 3, 4, 5.
• The recommended initial bolus dose is 0.25 mg/kg given over 2 minutes, although some studies suggest that a lower dose of 0.1 mg/kg may be effective in certain populations 3, 4.
• The maintenance infusion dose is typically 5 to 15 mg/h, although this may need to be adjusted based on the patient's response to treatment 4, 5.

Administration and Monitoring

• Diltiazem should be administered intravenously, with careful monitoring of the patient's heart rate and blood pressure 3, 4, 5.
• The patient's response to treatment should be closely monitored, with adjustments made to the dose as needed to achieve the desired heart rate or conversion to sinus rhythm 3, 4, 5.

Efficacy and Safety

• Diltiazem has been shown to be effective in reducing heart rate and converting supraventricular tachycardia to sinus rhythm in a significant proportion of patients 3, 4, 5, 6.
• The drug is generally well tolerated, with few significant side effects reported in clinical studies 3, 4, 5, 6.
• However, caution should be exercised when using diltiazem in patients with certain underlying medical conditions, such as sick sinus syndrome or congestive heart failure 3, 5.