Dronedarone

Dronedarone (also known as SR33589) is a drug under development by Sanofi-Aventis, mainly for the indication of cardiac arrhythmias (irregular heartbeat). It is currently in phase III trials for atrial fibrillation and in patients with an implantable cardioverter-defibrillator (ICD); a trial in heart failure was stopped as an interim analysis showed a possible increase in heart failure deaths.

Chemically it is a benzofuran derivative related to amiodarone, a popular antiarrhythmic the use of which is limited to toxicity due its high iodine content (pulmonary fibrosis, thyroid disease) as well as by liver disease. Dronedarone lacks the iodine, and is expected to have less toxicity, yet it displays amiodarone-like class III antiarrhytmic activity in vitro and in clinical trials.

In a 2007 trial in atrial fibrillation, dronedarone was significantly more effective than placebo in maintaining sinus rhythm, with no difference in lung and thyroid function in the short term.