The multiple modes of action of propafenone.
Previous studies of widely different concentrations of propafenone in various species have reported that in addition to having class 1 antiarrhythmic action, the drug was a beta adrenoceptor blocker and a calcium antagonist. High concentration shortened action potential duration in animal experiments, but Q-T interval was reported as being lengthened in man. It was thought desirable to study the effects of propafenone over a range of concentrations equivalent to those used clinically in various cardiac tissues of a single species, the rabbit. It was concluded that although the primary action of propafenone was on fast inward current, the drug being categorised as of group 1c, its potency as a beta blocker was sufficient for the effect to be of clinical significance. Its potency as a calcium antagonist was relatively weak. Action potential duration and effective refractory period were lengthened in both atrium and ventricle, the effects being long-lasting and persisting on wash-out of the drug when other measurements had returned to control values.
D000200:Action Potentials / Q000187:drug effects; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D005260:Female; D008297:Male; D011405:Propafenone; D011427:Propiophenones / Q000494:pharmacology*; D011690:Purkinje Fibers / Q000187:drug effects; D011817:Rabbits
D000319:Adrenergic beta-Antagonists; D000889:Anti-Arrhythmia Agents; D002121:Calcium Channel Blockers; D011427:Propiophenones; D011405:Propafenone