RESUMO
UNLABELLED: Rivaroxaban, a selective inhibitor of active factor X, is metabolized by cytochrom P450 3A4 (CYP3A4) and is a substrate for transporter protein--P-glycoprotein (P-gp). Amiodarone, an antiarrhytmic agent, is classified as moderate CYP3A4 and P-gp inhibitor. A CASE REPORT: A 75-year-old male, who underwent lobectomy for bronchiectasis many years ago, is presented. For one year the patient was treated with rivaroxaban (20 mg/d) due to venous thromboembolism and recurrent episodes of atrial fibrillation. Two weeks after amiodarone initiation (200 mg/d) hemoptysis occurred and computed tomography revealed unilateral pulmonary infiltrates with ground-glass opacities limited to the lower lobe of the left lung. The symptoms disappeared following discontinuation of the two medications and did not recur while rivaroxaban was reintroduced in a dose of 15 mg/d; measurement of anti-Xa activity confirmed it as a therapeutic dose. Amiodarone, that had been used for a short time and well tolerated a few years before, was definitely withdrawn. CONCLUSIONS: The authors suggest, that the concomitant use of rivaroxaban and amiodarone should be very careful in patients with a history of pulmonary disease.