04. Medications That Cause QT Prolongation

Any substance that can block the inward rectifying potassium channel can cause QT prolongation.

Extensive list and resource available at: www.crediblemeds.org/pdftemp/pdf/CompositeList.pdf

Top 5 classes to consider:

  1. Antiarrhythmics: quinidine, procainamide, disopyramide, amiodarone, sotalol, ibutilide, dofetilide, sematilide, mibefradil.
  2. Psychiatric medications: phenothiazines (thioridazine), tricyclic antidepressants, butyrophenones (haloperidol, droperidol), SSRIs, risperidone, methadone.
  3. Antibiotics: erythromycin, azithromycin, clarithromycin, TMP/SMX, pentamidine, ketoconazole, itraconazole, fluconazole, ampicillin, fluoroquinolones, chloroquine, mefloquine, spiramycin, halofantrine.
  4. GI meds: antiemetics (ondansetron, metoclopramide, compazine, prochlorperazine), cisapride (not on the U.S. market), droperidol.
  5. Antihistamines: diphenhydramine, hydroxyzine, terfenadine, astemizole.

Gupta A, Lawrence AT, Krishnan K, et al. Current concepts in the mechanisms and management of drug-induced QT prolongation and torsade de pointes. Am Heart J 2007;153:891-899.

Trinkley KE, Page RL 2nd, Lien H, Yamanouye K, Tisdale JE. QT interval prolongation and the risk of torsades de pointes: essentials for clinicians. Curr Med Res Opin. 2013 Dec;29(12):1719-26.