Comparison of the cardiac electrophysiology and general toxicology of two formulations of intravenous amiodarone in dogs.

Intravenous amiodarone (AIV) must be administered slowly after dilution to avoid hypotension, which is due to the cosolvents polysorbate 80 and benzyl alcohol used in its formulation. PM101 is a formulation of amiodarone devoid of these cosolvents, which enables bolus administration. We evaluated any potential toxicity or exaggerated adverse cardiac electrophysiologic effects of PM101 compared with AIV and control. Beagle dogs were treated with the human-equivalent amiodarone loading dose (2.14 mg/kg) with PM101 (bolus push) or AIV (10 min infusion in the toxicology study and bolus push in the electrophysiology study) followed by maintenance infusion (0.014 mg kg(-1) min(-1) through 6 h followed by 0.007 mg kg(-1) min(-1) through 14 days) or a control. General toxicology was assessed in conscious dogs over 14 days. Cardiac electrophysiology was assessed in a separate cohort of anesthetized dogs during the first 20 min of dosing. In the toxicology study, dosing in all animals in the AIV group was terminated within 17 min of initiation due to a severe hypersensitivity reaction. There were no acute adverse clinical signs in the PM101 or control groups. There were no significant effects on body weight or ECG parameters, and no adverse histomorphologic changes were seen in dogs that received PM101 or AIV. No significant exaggerated cardiac electrophysiologic effects of the approved doses PM101 or AIV were observed. PM101 may represent a formulation of intravenous amiodarone that could be administered rapidly without dilution in the setting of life-threatening cardiac arrhythmias.