What is the appropriate dosing for Diltiazem (Calcium Channel Blocker)?

From the Guidelines

Diltiazem should be dosed at an initial 15 to 20 mg (0.25 mg/kg) IV over 2 minutes for stable, narrow-complex tachycardias or to control ventricular rate in patients with atrial fibrillation or atrial flutter, with additional doses of 20 to 25 mg (0.35 mg/kg) IV in 15 minutes if needed, and a maintenance infusion of 5 to 15 mg/h IV. This dosing is based on the 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care 1.

Key Considerations

• The dosing of Diltiazem may vary depending on the specific indication and patient response.
• It is essential to monitor for side effects such as hypotension, bradycardia, and precipitation of heart failure, especially in patients with pre-existing heart failure or those taking other medications that may interact with Diltiazem.
• Diltiazem should only be given to patients with narrow-complex tachycardias (regular or irregular) and avoided in patients with heart failure and pre-excited AF or flutter or rhythms consistent with VT.

Administration and Monitoring

• Diltiazem should be administered IV over 2 minutes, with a maintenance infusion titrated to achieve the desired heart rate control.
• Patients should be closely monitored for changes in blood pressure, heart rate, and ECG during initiation and dose adjustments of Diltiazem.
• Common side effects of Diltiazem include hypotension, bradycardia, headache, and constipation, which should be managed promptly to minimize their impact on patient outcomes.

From the FDA Drug Label

DOSAGE AND ADMINISTRATION Exertional Angina Pectoris Due to Atherosclerotic Coronary Artery Disease or Angina Pectoris at Rest Due to Coronary Artery Spasm: Dosage must be adjusted to each patient’s needs Starting with 30 mg four times daily, before meals and at bedtime, dosage should be increased gradually (given in divided doses three or four times daily) at 1- to 2-day intervals until optimum response is obtained. Although individual patients may respond to any dosage level, the average optimum dosage range appears to be 180 to 360 mg/day The appropriate dosing for Diltiazem is to start with 30 mg four times daily and increase gradually every 1-2 days until an optimum response is obtained, with an average optimum dosage range of 180 to 360 mg/day 2.

• The dosage should be adjusted to each patient's needs.
• The tablets may be swallowed whole, crushed, or chewed, but should not be split.

From the Research

Diltiazem Dosing

• The appropriate dosing for Diltiazem, a calcium channel blocker, varies depending on the condition being treated, such as hypertension or angina 3, 4, 5, 6, 7.
• For hypertension, the dose of Diltiazem required is commonly 360 mg/day, while for angina, the dose is commonly 240 mg/day 3.
• However, studies have shown that Diltiazem is often underdosed, and when properly dosed, it may be the single most potent antihypertensive overall 3.
• A linear dose-response relationship between Diltiazem dose and blood pressure lowering has been observed, with the 90-120 mg/day range being the "no-effect dose" 3.
• For stable angina, a sustained-release formulation of Diltiazem administered once daily at doses of 200-300 mg has been shown to be effective and safe 5, 6.
• In patients with hypertension, a novel, once-daily, long-acting formulation of Diltiazem HCl (DTZ-LA) has been developed, which effectively reduces blood pressure in a dose-dependent fashion over a 24-h dosing interval 4.
• The efficacy and safety of DTZ-LA have been compared to other antihypertensive agents, such as amlodipine and ramipril, and have been shown to be effective in reducing morning blood pressure and exercise tolerance in patients with angina pectoris 4.
• The dose of Diltiazem can be titrated to doses of 540 mg/day, and it has been shown to be safe and well-tolerated, even at high doses 4.

Key Findings

• Diltiazem dose for hypertension: 360 mg/day 3
• Diltiazem dose for angina: 240 mg/day 3
• Sustained-release formulation for stable angina: 200-300 mg once daily 5, 6
• Long-acting formulation for hypertension: DTZ-LA, 540 mg/day 4
• Diltiazem has a linear dose-response relationship with blood pressure lowering 3
• Diltiazem is often underdosed, but when properly dosed, it may be the single most potent antihypertensive overall 3