Isolated Neutropenia: An Unexplored Side Effect of Amiodarone.

Amiodarone has been widely used for the treatment of various arrhythmias. It is a potent P450 inhibitor leading to interaction with many commonly prescribed drugs. Also, due to its long half-life, lipophilicity, and broad tissue distribution, it can cause a wide range of toxicities. A 62-year-old male with the unknown past medical history presented to the emergency department following a grand mal seizure. The patient initially presented with atrial flutter, which was controlled with beta blockers but was switched to amiodarone after 2 weeks when he developed atrial fibrillation with the rapid ventricular response. Approximately 1 month into his hospital stay, the patient developed severe isolated neutropenia. After ruling out other etiologies, amiodarone was withdrawn. The patient's absolute neutrophil count recovered 3 days after discontinuation of amiodarone.