RESUMEN
OBJECTIVE: Hydroxychloroquine (HCQ) is widely used in patients with systemic lupus erythematosus (SLE) due to its immunomodulatory properties. Antidepressants are commonly used in patients with fibromyalgia syndrome (FMS). Both HCQ and antidepressants are reported to cause QTc prolongation, which potentially increases the risk for a lethal ventricular arrhythmia that can result in sudden death. The objective of the study is to investigate the risk of QTc prolongation associated with HCQ use concomitantly with antidepressants in lupus patients with FMS. METHODS: Outpatient 12-lead electrocardiograms (ECGs) were extracted from an electronic medical record and QTc intervals were calculated using the Bazett's formula. QTc intervals in 135 lupus patients treated with HCQ with or without antidepressants were analyzed. RESULTS: We found taking HCQ was associated with mild QTc prolongation, and the prolongation was not affected by the length of time of HCQ use or the accumulated dose of HCQ. Concurrent use of HCQ and antidepressants had not further increased QTc intervals in this cohort. However, four patients on HCQ alone and three patients on HCQ and antidepressants were found QTc interval more than 500 milliseconds and most of these patients had underlying cardiological conditions. CONCLUSIONS: It is important to evaluate lupus patient with ECG before and after starting HCQ, though our study suggests that while HCQ use did prolong the QTc in some, but the overall prolongation was subclinical, with or without antidepressants. ECG monitoring therefore is essential to identify new changes potentially related to drug use.