What is the appropriate dose of Diltiazem (diltiazem) for a 208-pound female patient with atrial fibrillation (afib) and tachycardia, with a heart rate of 145 beats per minute?

From the Guidelines

For a 208-pound female with atrial fibrillation and a heart rate of 145 beats per minute, I recommend starting with intravenous diltiazem at a dose of 0.25 mg/kg (about 23-24 mg) administered over 2 minutes, as supported by the 2010 American Heart Association guidelines 1.

Key Considerations

• The dose of diltiazem is based on the patient's weight, with a recommended initial dose of 15 mg to 20 mg (0.25 mg/kg) IV over 2 minutes, as stated in the guidelines 1.
• If the heart rate remains elevated after 15 minutes, an additional dose of 20 mg to 25 mg (0.35 mg/kg) can be administered, as per the guidelines 1.
• The maintenance infusion dose is 5 mg/hour to 15 mg/hour, titrated to heart rate, as recommended in the guidelines 1.
• It is essential to monitor the patient's blood pressure, as diltiazem can cause hypotension, and also monitor for bradycardia and heart block, especially if the patient is on other rate-controlling medications.
• The 2006 ACC/AHA/ESC guidelines for the management of patients with atrial fibrillation also support the use of diltiazem for heart rate control, with a recommended dose of 0.25 mg/kg IV over 2 min and a maintenance dose of 5 to 15 mg/h IV 1.

Important Factors

• The patient's weight and heart rate should be closely monitored during administration of diltiazem.
• Caution should be exercised when using diltiazem in patients with heart failure, hypotension, or significant liver or kidney disease.
• Ensuring the patient has adequate hydration status before administration is crucial.
• The guidelines from both 2010 and 2006 support the use of diltiazem for heart rate control in atrial fibrillation, with the 2010 guidelines providing more specific dosing recommendations 1.

From the Research

Diltiazem Dosing for Atrial Fibrillation

• The appropriate dose of diltiazem for a 208-pound female with atrial fibrillation and a heart rate of 145 beats per minute can be determined based on weight-based dosing strategies.
• A study published in 2021 2 found that a mean weight-based dose of 0.13 mg/kg diltiazem was effective in achieving heart rate control in patients with atrial fibrillation with rapid ventricular rate.
• Another study published in 2023 3 found that weight-based dosing of 0.1875 to 0.3125 mg/kg was associated with improved rate control and reduced need for rescue therapy compared to lower doses.
• Based on these studies, a suitable dose for a 208-pound (94 kg) female would be approximately 12.2-29.4 mg of diltiazem, considering the weight-based dosing range of 0.13 mg/kg 2 to 0.3125 mg/kg 3.

Comparison with Other Studies

• A study published in 2015 4 compared the effectiveness of diltiazem and metoprolol in managing atrial fibrillation or flutter with rapid ventricular rate, but did not provide specific dosing recommendations based on weight.
• Another study published in 2024 5 examined the combination therapy of beta-blockers and digoxin in patients with atrial fibrillation, but did not provide relevant information on diltiazem dosing.

Key Findings

• Weight-based dosing of diltiazem is associated with improved heart rate control and reduced need for rescue therapy in patients with atrial fibrillation with rapid ventricular rate 2, 3.
• The optimal dose of diltiazem for a 208-pound female with atrial fibrillation and a heart rate of 145 beats per minute is likely to be in the range of 12.2-29.4 mg, based on weight-based dosing strategies 2, 3.