Medications with Potential to Prolong QT Interval

Several medications, including methadone, have the potential to prolong the QT interval.

PharmaNet should be reviewed for drugs that may potentially cause a prolonged QT interval prior to initiating or refilling a methadone prescription. Commonly prescribed drugs that may prolong the QT interval are included in the table below. In addition, Credible Meds provides a list of QT-prolonging drugs, and an overview of prolonged QT intervals and Torsades de Pointes.

When possible, avoid prescribing multiple QT prolonging medications simultaneously, especially in patients that have other risk factors. If a prolonged QTc is found or there are questions about safely prescribing multiple QT-prolonging medications simultaneously, prescribers are encouraged to consult the 24/7 Line or the RACE app.

Commonly Used Drugs That May Cause Prolonged QT Intervals

Drug Class Examples
Antiarrhythmics-
Class I and III antiarrhythmics
Amiodarone
Sotalol
Quinidine
Procainamide
Dofetilide
Ibutilide
Antimicrobial agents-
Fluoroquinolones,
Macrolides,
Antifungal agents
Ciprofloxacin
Moxifloxacin
Levofloxacin
Erythromycin
Ketoconazole
Itraconazole
Antipsychotic agents Haloperidol
Thioridazine
Quetiapine
Droperidol
Ziprasidone
Risperidone
Clozapine
Antidepressants Amitriptyline
Desipramine
Imipramine
Doxepin
Fluoxetine
Sertraline
Venlafaxine
Antivirals Nelfinavir
Antimalarials Chloroquine
Mefloquine
Opioid analgesic/opioid agonist Methadone
Other Cisapride
Sumatriptan
Zolmitriptan
Arsenic
Dolasetron
Tacrolimus
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