Comparative effects of rapid bolus administration of aqueous amiodarone versus 10-minute cordarone I.v. infusion on mean arterial blood pressure in conscious dogs.

Objective: This study was designed to test the hypothesis that rapid bolus administration of an aqueous formulation of intravenous amiodarone causes less hypotension than a 10-minute infusion of the standard formulation, Cordarone IV. Hypotension was the most common adverse event reported with Cordarone IV. The hypotension was not dose related, but related to the rate of infusion. Therefore, product labeling calls Cordarone and its generic formulations to be administered over 10 minutes. Cordarone IV contains polysorbate 80 and benzyl alcohol, each causes hypotension. A new aqueous formulation of amiodarone (Amio-Aqueous) does not contain these agents and therefore may cause less hypotension.

Methods: Six conscious beagle dogs were instrumented with a telemetric device for blood pressure monitoring. The study was conducted on 5 days. On the first 2 days, a 10-min infusion or a bolus of D(5)W was administered (placebo). Over the following 3 days, the dogs received (in randomized order, one per day) a 10-min infusion of 2.5 mg/kg Cordarone IV and boluses of 2.5 mg/kg and 5.0 mg/kg Amio-Aqueous injected over 2 to 5 sec. The dogs were monitored for 2 hrs after dosing.

Results: Compared to placebo, boluses of aqueous amiodarone produced no significant changes in the mean arterial blood pressure (MABP). In contrast, Cordarone infusion produced significant decreases in MABP that lasted for at least 2 hrs (p < 0.001).

Conclusion: Amio-Aqueous had significantly better hemodynamic profile permitting rapid intravenous administration. This is a significant advantage over the standard formulation, because Cordarone cannot be administered by rapid bolus due to excipient-related hypotension.