Autoimmune-Hemolytic Anemia Associated with Montelukast and Zafirlukast Therapy in a Patient with Hepatitis C

Abstract

Objective To report a case of autoimmune-hemolytic anemia (AIHA) associated with montelukast and, subsequently, zafirlukast in a patient with hepatitis C. Case Summary A 57-year-old white man with known hepatitis C presented with jaundice, bilateral lower-extremity edema, fatigue, and exertion for 3 weeks. He started using montelukast a week prior to experiencing these symptoms. After consultation with his primary care provider, montelukast was replaced with zafirlukast, which improved edema but other symptoms persisted. The patient was admitted to the hospital with symptoms, physical findings, and laboratory tests suggestive of AIHA. Leukotriene receptor antagonist therapy was discontinued and the patient received treatment with red blood cell transfusions and corticosteroids. The patient's hemoglobin stabilized within 9 days. Discussion AIHA may occur idiopathically or secondarily in association with drug or chemical exposures, lymphoproliferative disorders, collagen vascular diseases, or malignancies. Several mechanisms for drug-induced AIHA have been elucidated; however, direct laboratory testing is difficult. Therefore, diagnosis of drug-induced AIHA should be made when other causes have been ruled out, when temporal relation can be made, and when improvement of symptoms occurs upon discontinuation of the suspected agent. Conclusion Over 100 drugs have been implicated in the formation of warm antibody hemolytic anemia; however, there are currently no reports of leukotriene receptor antagonists associated with AIHA. Even though, in this case report, the patient had coexisting hepatitis C, which can cause AIHA alone, an objective causality assessment revealed that the AIHA was possibly due to montelukast and zafirlukast.