The FDA and the manufacturer (Sanofi-Aventis) have warned healthcare professionals that use of dronedarone (Multaq), an analog of amiodarone (Cordarone, and others) approved in 2009 for treatment of atrial fibrillation,1,2 has been associated with "several" cases of severe liver injury and hepatic failure, including two that required liver transplants. Both transplants were in women about 70 years old; one had taken the drug for 4.5 months and the other for 6 months. According to the FDA, 147,000 patients have taken dronedarone.3 A new warning in the package insert recommends monitoring hepatic enzymes, especially during the first 6 months of treatment.