Possible Interaction: Anti-Arrhythmia Agents and Quinidine

“The results clearly indicate that at the dosage used, the four antiarrhythmic agents ( quinidine , disopyramide, prajmaliumbitartrate, propafenone) exert a negative inotropic effect on left ventricular function as far as it can be judged from the measurement of STI.”

“Other antiarrhythmics such as beta-blockers, calcium channel blockers, and amiodarone have been used effectively also; however, some antiarrhythmics such as lidocaine, mexiletine, propafenone, and quinidine may exacerbate neuromuscular symptoms and should be used cautiously.”

“Dofetilide, d,l-sotalol and quinidine exhibited an increase in the manifestation of pro-arrhythmia markers.”

“The effective use of quinidine as an antiarrhythmic agent is frequently curtailed by one of its most common side effects—relentless diarrhea.”

“However, maps on quinidine differed as a function of antiarrhythmic efficacy.”

“The addition of quinidine , which prolongs repolarization of the action potential in vitro, enhanced the antiarrhythmic efficacy of mexiletine, which shortens the action potential duration in vitro.”

“Although quinidine may induce proarrhythmia , the contributing mechanisms remain incompletely understood.”

“Both flecainide and quinidine then prevented both induced and spontaneous atrial arrhythmias in all the arrhythmic WT and Scn5a+/− hearts, in contrast to their differing ventricular effects.”

“The differences may influence the actions of quinidine on repolarization of the heart in situ and determine both the proarrhythmic and antiarrhythmic actions of the drug.”

“The ability of quinidine in therapeutic concentrations to prolong repolarization at rapid heart rates can contribute to its antiarrhythmic efficacy.”