Comparing efficacy and safety of weight based and non-weight based intravenous dosing of Diltiazem

Purpose:
The purpose of this study was to compare the efficacy and safety of 2 IV Diltiazem bolus dose regimens (weight vs non-weight based) in the treatment of atrial fibrillation in certain high risk patient populations.

Background/Significance:
The recent nationwide shortage of Diltiazem led our hospital to revise dosing and bolusing procedures to utilize smart pump technology. This allowed for non-weight based bolus administration from the intravenous bag to conserve supplies. The American Heart Association/Advanced Cardiac Life Support guidelines include weight based versus non-weight based dosing of Diltiazem but our providers questioned the efficacy and safety of administering non-weight based doses in high risk populations.

Methods:
A retrospective exploratory design was used. Outcome measures included need for second bolus; time to rate control; baseline and post bolus heart rate and blood pressures; patient demographics; primary patient diagnosis; and use of other vasoactive medications. Patients started on intravenous Diltiazem were chosen in a convenience sample. Patients excluded were those undergoing cardio version; those with baseline systolic blood pressure less than 100mm Hg, patients with acute, decompensated heart failure, renal failure or a pacemaker.

Results:
Multifactor ANOVA was used to analyze the differences in the subject's demographic and outcomes data. No significant differences were noted in demographics between non-weight based and weight-based dosed groups. No significant differences were noted in use of second bolus between groups.No significant correlation noted between dosing regimens and systolic blood pressure less than 90 mm Hg. Analysis of time to reach therapeutic heart rate between dosing regimens showed a significant difference with weight-based dosing taking longer.(p=0.035)

Conclusions and Implications for Practice:
The Diltiazem drug shortage necessitated altering our dosing regimen. This led to questions of efficacy and safety in high risk patients when age/weight/risk factors were not a determinate. This study supports the AHA/ACLS guidelines for non-weight based dosing of Diltiazem.