title: Suppression of arrhythmias within hours after a single oral dose of amiodarone and relation to plasma and myocardial concentrations.
abstract: In 65 patients a single oral dose of amiodarone (30 mg/kg) produced an antiarrhythmic effect on supraventricular or ventricular arrhythmias within 3 to 8 hours and lasted for 17 to 19 hours. On the second day a 15-mg/kg dose reproduced this effect within 3 to 9 hours. Plasma concentration of amiodarone increased to a maximum (2.2 +/- 1.7 mg/liter) mean +/- standard deviation) at 6 +/- 3.5 hours and plasma levels of N-desethylamiodarone (NDA) rose to 0.2 +/- 0.08 mg/liter at 12 +/- 6.4 hours. Sixty-one other patients were given a single 30-mg/kg dose 7 hours to 4 days before open heart surgery. Biopsies of the right atrial and left ventricular walls were taken during surgery. Myocardial concentration of amiodarone was maximal in the atrium after 7 hours (13 +/- 8 mg/kg) and in the ventricle after 24 hours (17 +/- 11 mg/kg). NDA myocardial concentration increased progressively until 24 hours and then remained stable over 4 days (1.5 mg/kg). The amiodarone myocardial to plasma concentration ratio was similar in the atrium and in the ventricle and averaged 22 and 10 for amiodarone and NDA, respectively. A significant relation existed between amiodarone concentration and the effect on ventricular premature complexes (r = 0.74, p less than 0.001) and between amiodarone plasma concentration and the effect on the atrioventricular conduction (r = 0.58, p less than 0.001). The plasma concentration of amiodarone corresponding to a 60% decrease in arrhythmias averaged 1.5 to 2 mg/liter.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000638:Amiodarone / Q000009:adverse effects / Q000031:analogs & derivatives / Q000097:blood / Q000494:pharmacology*; D001145:Arrhythmias, Cardiac / Q000188:drug therapy* / Q000503:physiopathology; D001281:Atrial Fibrillation / Q000188:drug therapy / Q000503:physiopathology; D001283:Atrioventricular Node / Q000503:physiopathology; D001572:Benzofurans / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography; D005260:Female; D006325:Heart Atria / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism*; D013610:Tachycardia / Q000188:drug therapy / Q000503:physiopathology; D013997:Time Factors
chemical_list: D001572:Benzofurans; C036116:desethylamiodarone; D000638:Amiodarone