OBJECTIVES: Antiarrhythmic drugs (AADs) are considered the first-line treatment of atrial fibrillation (AF). However, they present a high adverse effects (AEs) rate. The aim of the present study is to know the health resources and the costs associated with the management of AEs of main AADs. METHODS: The incidence of AE’s of main AADs (amiodarone, sotalol, flecainide and propafenone) has been obtained from the Summary of product characteristics or correspondent clinical trials. The use of health resources associated with the management of the AEs has been evaluated by a panel of cardiology experts. Finally, all these clinical data regarding AE´s incidence derived, has been combined with economic data from the Spanish literature and e- salud data,an Spanish database about health care costs. The study has been carried using National Health System perspective. RESULTS: The most expensive AEs have been pulmonary fibrosis: €2,177.49, cardiac events (mainly tachycardia or bradycardia):€1,422.08, and endocrine disorders (as hyperthyroidism: €244.06€ and  hypothyroidsm: €239.06 €). When costs are analyzed in relation with the drug to which are associated, results are as follow: sotalol has been associated with the highest costs: €269.42, followed by  flecainide: 132.25 €, and amiodarone:127,82, whereas  propafenone has been associated to the lowest  cost: €48.09. However, although amiodarone is not the AAD associated with the highest cost, considering current Spanish AADs market, it is the one that has more economic repercussion. CONCLUSIONS: Current AADs may cause AEs and their management is related to health resources consumption. Pulmonary and cardiac events have been associated to the major cost. Considering current clinical practice in Spain, amiodarone is the treatment that supposes a major budget impact for the National Health Service.