Drugs Home > QT-Prolonging Medications

There are a number of medications that can prolong the QT interval, which could lead to a dangerous irregular heart rhythm. These QT-prolonging medications include methadone, certain antibiotics, cyclobenzaprine, and certain cancer medicines. People with long QT syndrome should not take any of these drugs. Using these medications together could also increase the risk of QT prolongation.

QT-Prolonging Medications: An Overview

Many medications increase the risk of QT prolongation, a dangerous type of irregular heart rhythm (arrhythmia). The QT interval is a section of the electrocardiogram (ECG or EKG), and having a QT interval that is too long can be dangerous. If you already have a long QT interval (if you have long QT syndrome), you probably need to avoid medications that prolong the QT interval. Also, QT-prolonging medications should generally not be used in combination, as this increases the risk of problems.

List of QT-Prolonging Medications

The list that follows does not include every medication that prolongs the QT interval. Additionally, some of these medications are more likely to cause QT prolongation than others. This list does not include several medications that have been withdrawn from the market in the United States (due to problems with QT prolongation). Some medications that prolong the QT interval include:


  • Certain arrhythmia medications, including:


  • Certain cancer medications, including:


  • Certain nausea and vomiting medications, including:








Written by/reviewed by:
Last reviewed by: Kristi Monson, PharmD;
Last updated/reviewed:
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