N-Acetylprocainamide: An Active Metabolite of Procainamide

SummaryN-Acetylprocainamide has been detected in the plasma samples of each of four patients receiving procainamide. The metabolite was identified from tlc data and its identity confirmed by gas chomatographic-mass spectroscopic analysis. The metabolite was also detected in the whole blood of Sprague-Dawley rats after administration of PA. NAPA · HCI when injected ip into 42- to 49- day-old ICR male mice prevented coarse ventricular fibrillation caused by deep chloroform anesthesia and resultant hypoxia. NAPA · HCl reduced aconitine-induced arrhythmia to atrial flutter or atrial tachycardia with varying degrees of A-V block in three dogs. Analysis by tlc indicated that the mice, dogs, and rats did not deacetylate NAPA during the period of pharmacologic testing. NAPA was found to cause less ferrihemoglobin in Sprague-Dawley rats than did PA.