{"entity":{"id":"qt-prolongation","kind":"term","name":"QT prolongation","aka":["QTc prolongation","QTc","QT interval","prolonged QT","QT","ECG monitoring","electrocardiogram","hERG","hERG inhibition","torsades","torsades de pointes","ventricular arrhythmia","electrolyte monitoring"],"tldr":"A change on the heart's electrical trace, caused by some drugs blocking a potassium channel (hERG), that in rare cases sets off a dangerous rhythm. Drugs that do this need ECG checks and care with other medicines and low potassium or magnesium.","summary":"Off-target hERG inhibition is common among kinase inhibitors (vandetanib, nilotinib, ribociclib, osimertinib, mobocertinib, selpercatinib, ivosidenib) and other drugs (arsenic trioxide, ondansetron, methadone); labels require baseline and periodic ECGs and electrolyte correction, and combining QT-prolonging drugs is avoided. Clinically important arrhythmia is rare, but QT prolongation has delayed or narrowed approvals and is screened for in early drug development (thorough QT studies). A QTc above 500 ms or an increase over 60 ms usually triggers dose interruption.","asOf":"2026-09-09","wikipedia":"https://en.wikipedia.org/wiki/Long_QT_syndrome#Drug-induced","links":[{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/Long_QT_syndrome#Drug-induced"}],"tags":[],"related":["cardiotoxicity","therapeutic-index","tki-term"],"cancers":[],"sections":["supportive-care"],"technologies":[],"targets":[],"drugs":["nilotinib","ribociclib","osimertinib","arsenic-trioxide"],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"category":"Side effects"},"route":"/terms/qt-prolongation/","neighbours":{"term":[{"id":"cardiotoxicity","kind":"term","name":"Cardiotoxicity (LVEF decline, cardiomyopathy)","route":"/terms/cardiotoxicity/"},{"id":"therapeutic-index","kind":"term","name":"Therapeutic index (therapeutic window)","route":"/terms/therapeutic-index/"},{"id":"tki-term","kind":"term","name":"Tyrosine kinase inhibitor (TKI)","route":"/terms/tki-term/"}],"section":[{"id":"supportive-care","kind":"section","name":"Supportive Care & Survivorship","route":"/fronts/supportive-care/"}],"drug":[{"id":"arsenic-trioxide","kind":"drug","name":"Arsenic trioxide","route":"/drugs/arsenic-trioxide/"},{"id":"nilotinib","kind":"drug","name":"Nilotinib","route":"/drugs/nilotinib/"},{"id":"osimertinib","kind":"drug","name":"Osimertinib","route":"/drugs/osimertinib/"},{"id":"ribociclib","kind":"drug","name":"Ribociclib","route":"/drugs/ribociclib/"}],"technology":[{"id":"cardiac-biomarker-monitoring","kind":"technology","name":"Troponin and natriuretic peptide monitoring during cancer treatment","route":"/technologies/cardiac-biomarker-monitoring/"}]}}