Major
Probable
説明
Hydroxychloroquine and ondansetron both prolong cardiac repolarization via hERG blockade; concurrent use substantially elevates arrhythmia risk.
機序
Additive IKr (hERG) blockade prolongs QTc in a dose-dependent manner; hydroxychloroquine may also affect sodium and calcium currents.
臨床的意義
Both drugs carry independent QT prolongation warnings; combination has been linked to torsades de pointes in case reports.
対処法
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.