PURPOSE: Our aim was to evaluate whether dronedarone authorization impacts antiarrhythmic drug prescribing in Sweden and Emilia Romagna (Italy). METHODS: Prescriptions of classes I and III antiarrhythmics, expressed as defined daily doses per thousand inhabitants per day (DDD/TID) were monthly using information collected from pharmacy-reimbursed databases. Interrupted time series analysis was applied to compare prescription data over the 2009-2011 period. RESULTS: In Emilia Romagna, the overall consumption of antiarrhythmics was six times as high as in Sweden (7.6 vs. 1.2 DDD/TID). In the first year on the market, dronedarone represented 1.0 % in Italy and 10.7 % in Sweden of the overall antiarrhythmic prescriptions. In Sweden, dronedarone authorization generated an increase in the prescription trend of antiarrhythmics (trend change +0.02; p < 0.001) without variation in amiodarone use In Emilia Romagna, dronedarone marketing did not influence the prescription pattern of either overall antiarrhythmics or amiodarone. CONCLUSIONS: Emilia Romagna and Sweden substantially differ in terms of overall antiarrhythmic use. Although clinical guidelines place dronedarone among first-choice treatments for atrial fibrillation, amiodarone prescribing was not affected in either country by the entry of dronedarone, probably due to a cautious approach by clinicians in line with regulatory recommendations and safety warnings.