Major
Probable
Mô tả
Hydroxychloroquine and ondansetron both prolong cardiac repolarization via hERG blockade; concurrent use substantially elevates arrhythmia risk.
Cơ chế
Additive IKr (hERG) blockade prolongs QTc in a dose-dependent manner; hydroxychloroquine may also affect sodium and calcium currents.
Ý nghĩa lâm sàng
Both drugs carry independent QT prolongation warnings; combination has been linked to torsades de pointes in case reports.
Xử trí
Avoid concurrent use; if antiemesis is needed during hydroxychloroquine therapy, choose a non-QT-prolonging agent such as metoclopramide (with its own caveats) or a corticosteroid-based antiemetic strategy.