Risk of QT Interval Prolongation Associated With Use of Hydroxychloroquine With or Without Concomitant Azithromycin Among Hospitalized Patients Testing Positive for Coronavirus Disease 2019 (COVID-19)

Cohort study (n=90) reported that patients treated with hydroxychloroquine for pneumonia associated with COVID-19 were at high risk of QTc prolongation, with greater risk in those concurrently treated with azithromycin.One case of torsades de pointes was reported.

SPS commentary:

19% and 3% of patients on hydroxychloroquine monotherapy had a QTc >500 ms and increase in QTc of 60 ms respectively, and 21% and 13% of patients on concurrent azithromycin had a QTc >500 ms and increase in QTc of 60 ms respectively.


An editorial discusses the findings of this study, and a smaller French case series which reported excessive prolongation of QTc in 14 of 40 patients (36%) in an intensive care unit, although with no cases of torsades de pointes.


The author notes that these findings underscore the potential risk associated with widespread use of hydroxychloroquine and the combination of hydroxychloroquine and azithromycin in ambulatory patients with known or suspected COVID-19, and suggest that clinicians should carefully weigh risks and benefits if considering hydroxychloroquine and azithromycin, with close monitoring of QTc and concomitant medication usage.


JAMA Cardiology

Resource links:


French case series: