Bedside Clinical Question:
· Is weight-based dosing for IV diltiazem in atrial fibrillation better than fixed dosing in treating atrial fibrillation? And which weight do we use?
Background:
· Traditionally, weight-based dosing is used for IV diltiazem in atrial fibrillation, 0.25 mg/kg followed by 0.35 mg, if the first dose is not effective.
· However, recent literature comparing a fixed 10 mg IV diltiazem dose to weight-based dosing has found similar success between the two strategies.
· The weight most commonly used is actual body weight.
Answer:
· In a study by Ross et al, they compared a fixed 10 mg dose to weight-based dosing and found similar success between the two strategies. Greater than 60% of patients in both groups achieved the primary outcome of successful treatment at the 15-minute mark post-dose.
· In another study by Zimmerman et al, they found no difference in total diltiazem dose needed between their study patients. The authors mention that about 30 mg of IV diltiazem was needed in each group. Of interest, it took a mean of approx. 2 hours for HR to drop below 100 bpm in both groups.
· Finally, in a study by Ward et al that explored different weight-based and non-weight-based dosing strategies, they found that overall, there was no difference in therapeutic response between the groups. However, when the authors looked at what is the best weight to use for weight-based dosing, they found that ideal body weight vs actual body weight was associated with higher therapeutic response.
Conclusion:
· Either weight-based dosing or a standard 10 mg dose is appropriate.
· In some patients, 30 mg of IV diltiazem may be needed.
· Consider using the 10 mg strategy in patients with initial borderline blood pressures, older adults, and/or expected to drop their blood pressure.
· If weight-based dosing is used, ideal body weight appears to achieve better outcomes.
Written and reviewed by: Joanne C Routsolias, PharmD, RN, BCPS
Clinical PharmD Specialist - Emergency Medicine/Toxicology
References:
· Ross AL, O'Sullivan DM, Drescher MJ, Krawczynski MA. Comparison of Weight-Based Dose vs. Standard Dose Diltiazem in Patients with Atrial Fibrillation Presenting to the Emergency Department. J Emerg Med. 2016 Oct;51(4):440-446. doi: 10.1016/j.jemermed.2016.05.036. Epub 2016 Jul 21. PMID: 27452987.
· Zimmerman DE, Jachim L, Iaria A, Brun C, Covvey JR. The effect of body weight on intravenous diltiazem in patients with atrial fibrillation with rapid ventricular response. J Clin Pharm Ther. 2018 Dec;43(6):855-859. doi: 10.1111/jcpt.12731. Epub 2018 Jun 28. PMID: 29956357
· Ward SM, Radke J, Calhoun C, Caporossi J, Hall GA, Matuskowitz AJ, Weeda ER, Weant KA. Weight-based versus non-weight-based diltiazem dosing in the setting of atrial fibrillation with rapid ventricular response. Am J Emerg Med. 2020 Nov;38(11):2271-2276. doi: 10.1016/j.ajem.2019.09.020. Epub 2019 Nov 15. PMID: 31753621.