Does treatment with hydroxychloroquine or chloroquine lead to QTc prolongation in children?

Background Hydroxychloroquine and chloroquine are drugs with a long history of therapeutic use in the prevention of both rheumatologic and infectious diseases. However, the cardiotoxic potential of therapy with these medications, particularly in children, remains a noted concern. Aim of review This review aims to identify whether treatment with hydroxychloroquine or chloroquine results in clinically meaningful QTc prolongation and increased risk of arrhythmia in comparison to baseline risk in the pediatric population. Key scientific concepts of review Out of the combined 65 children from the four included chloroquine studies with normal pre-treatment QTc intervals, 13 (20%) experienced clinically defined QTc prolongation (i.e., >440–500 ms). Of the combined 56 patients who were administered hydroxychloroquine across four studies, 5 (8.9%) patients experienced clinically defined QT or QTc prolongation. Such effects were found to be most prominent in the initial days of treatment. While QTc prolongation was reported in the majority of studies analyzed, the isolated medication effect is difficult to establish in the absence of placebo arms and randomization procedures. Although hydroxychloroquine and chloroquine may prolong the QT interval in children, there is little evidence to suggest that it commonly prolongs it to a clinically relevant or arrhythmogenic degree with short-term treatment.