QT Interval

TaperMD uses content from CredibleMeds® to create a flag for medications with potential cardiac risk.

The CredibleMeds® content contains drugs categorized by their potential to cause QT prolongation and/or torsades de pointes (TdP), a lethal arrhythmia.

General guidelines from CredibleMeds® include:

  • If possible, do not prescribe QT-prolonging drugs to anyone with a QT > 440ms (female) or 420ms (male).
  • Do not allow the QT to exceed 500ms during titration with these drugs.
  • Be aware of drug interactions that could result in greater exposure to the QT- prolonging drugs by blocking their metabolism or delaying clearance.
  • Electrolyte abnormalities, age and female sex increase the risk.

Visit CredibleMeds® for more detailed information on the issues they cover as well as summaries derived from the FDA drug monographs of QT/TDP issues.

Categories of risk assigned:

  • Drugs with known risk of TdP.
  • Drugs with possible risk of TdP.
  • Drugs with conditional risk of TdP – i.e., can cause TdP under certain conditions.
  • Drugs to be avoided by congenital Long QT patients.

The cumulative burden is important – you can also click on an individual drug to see if the full FDA label.

Reference(s):  Woosley, RL, Heise, CW and Romero, KA, Crediblemeds.org, QTdrugs List, June 2018, AZCERT, Inc. 1822 Innovation Park Dr., Oro Valley, AZ 85755]