Hydroxychloroquine-induced Atrioventricular Block in a Patient with Systemic Lupus Erythematosus: A Case Report

Abstract

Hydroxychloroquine sulfate (HCQ) is widely prescribed in the long-term treatment of systemic lupus erythematosus (SLE) and cutaneous lupus erythematosus (CLE). In Japan, the indications for SLE and CLE were obtained at 2015. We report a case of atrioventricular block (AVB) during HCQ therapy in a 29-year-old woman with SLE. On admission, her lupus nephritis was exacerbated and the administration of HCQ was started. Electrocardiography during HCQ treatment revealed second-degree AVB and sinus tachycardia. HCQ was then discontinued and the second-degree AVB disappeared, while first-degree AVB remained. Although, HCQ-induced AVB has been reported mainly in Europe and North America, no cases were observed in a Japanese phase III clinical trial and no case reports on HCQ-induced AVB have been reported in Japan. It seems that adverse cardiac events occur frequently when the duration and total dosage of HCQ are increased. The present case shows the need for monitoring of cardiac function to avoid life-threatening cardiac conduction disturbance.