FDA warning links Multaq to severe liver injury
The FDA is alerting healthcare professionals and patients about cases of rare, but severe liver injury, including two cases of acute liver failure leading to liver transplants in patients treated with the anti-arrhythmic drug dronedarone (Multaq, Sanofi-Aventis).

Dronedarone is used to treat abnormal heart rhythm in patients who have had atrial fibrillation or atrial flutter during the past six months. Dronedarone can reduce the risk of being hospitalized for these conditions, according to the FDA. The agent was approved with a Risk Evaluation and Mitigation Strategy with a goal of preventing its use in patients with severe heart failure or who have recently been in the hospital for heart failure. In a study of patients with these conditions, patients given dronedarone had a greater than two-fold increase in risk of death.

The agency has since received several case reports of hepatocellular liver injury and hepatic failure in patients treated with dronedarone, including two post-marketing reports of acute hepatic failure requiring transplantation. Because these reactions are reported voluntarily from a treatment population of unknown size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

The two cases of acute hepatic failure requiring transplantation occurred at 4.5 and six months after initiation of dronedarone in patients with previously normal hepatic serum enzymes. Both patients were female and approximately 70 years of age.

Since dronedarone's approval in July 2009 through October 2010, around 492,000 dronedarone prescriptions were dispensed and around 147,000 patients filled dronedarone prescriptions at outpatient retail pharmacies in the U.S., the FDA reported. Additional usage occurs in the hospital setting.