Background: Intravenous digoxin loading dose recommendations differ between clinical guidelines and Food and Drug Administration packaging for acute rate control.
Objective: The objective of this study was to assess the safety and efficacy of intravenous digoxin loading in patients who received ≤12 µg/kg and >12 µg/kg of digoxin using ideal body weight (IBW).
Methods: This single center retrospective cohort study with exempt status from the local Institutional Review Board included patients who received intravenous digoxin and had a serum digoxin concentration (SDC) drawn. Digoxin doses >36 hours after the first dose were excluded. Patients who received a total of >12 µg/kg and ≤12 µg/kg IBW were compared. The primary endpoint was frequency of SDCs ≥1.2 ng/mL, which have been shown to be associated with increased mortality.
Results: A total of 244 patients were included (144 receiving >12 µg/kg and 100 receiving ≤12 µg/kg). There were significantly more SDC ≥1.2 ng/mL in the >12 µg/kg group than the ≤12 µg/kg group (50.6% vs. 30.0%; adjusted odds ratio, 3.19; 95% confidence interval [CI]: 1.79-5.84), with no difference in rate control failure. Major limitations of the study include retrospective nature and possible selection bias.
Conclusion and relevance: Compared to patients who received digoxin doses ≤12 µg/kg IBW, patients who received >12 µg/kg IBW had higher rates of SDC ≥1.2 ng/mL. This suggests that appropriate weight-based dosing with 8 to 12 µg/kg IBW has the potential to be a safer approach to digoxin loading, rather than frequently used dosing strategies that result in doses >12 µg/kg.
Keywords: arrhythmias; digoxin; dose-response relationship; dosing; drug monitoring.