Atrial fibrillation occurring in a patient taking etanercept plus methotrexate for rheumatoid arthritis.

A 57-year-old man with nodular rheumatoid arthritis was started on a combination of etanercept and methotrexate. After treatment for five months on this therapy, he presented with new-onset atrial fibrillation. While this report is anecdotal, any new drug warrants intense monitoring for unexpected toxicities in the post-marketing period. Etanercept is being tried in patients with congestive heart failure, where TNF-a seems to be increased. Further surveillance and caution are suggested in patients with known coronary artery disease or atrial dysrhythmia.