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Cardiotoxicity of macrolides, ketolides and fluoroquinolones that prolong the QTc interval

Paul B Iannini1

  • 1Department of Medicine, Danbury Hospital, Danbury, CT 06810, USA. paul.iannini@danhosp.org

Expert Opinion on Drug Safety
|August 9, 2003
PubMed

Insights

Certain antibiotics like macrolides and fluoroquinolones can prolong cardiac repolarization, increasing arrhythmia risk. This risk is low but higher in patients with pre-existing cardiac conditions or those taking other heart-affecting medications.

Area of Science:

  • Pharmacology
  • Cardiology
  • Electrophysiology

Background:

  • Macrolides, ketolides, and fluoroquinolones are classes of antimicrobial agents.
  • These agents, including erythromycin, clarithromycin, gatifloxacin, moxifloxacin, levofloxacin, and telithromycin, are associated with cardiac repolarization prolongation.

Purpose of the Study:

  • To review the association between antimicrobial agents and cardiac repolarization.
  • To identify the risk factors and clinical outcomes related to drug-induced QT interval prolongation.

Main Methods:

  • Review of existing literature on antimicrobial agents and cardiac repolarization.
  • Analysis of HERG channel function and its role in QT interval prolongation.
  • Assessment of clinical data on associated arrhythmias, including Torsades de Pointes.

Main Results:

  • Antimicrobial agents can block HERG channel potassium current, prolonging the QTc interval.
  • Prolonged QTc interval increases the risk of polymorphic ventricular tachycardia, Torsades de Pointes, and ventricular fibrillation.
  • Risk factors include concomitant use of Type Ia or III anti-arrhythmic agents, other QTc-prolonging drugs, electrolyte disturbances, and underlying cardiac disease.

Conclusions:

  • The overall risk of ventricular arrhythmias with these agents is very small.
  • Risk can be further minimized by avoiding use in patients with multiple risk factors for Torsades de Pointes.
  • Erythromycin, clarithromycin, gatifloxacin, levofloxacin, and moxifloxacin present a decreasing order of risk, with telithromycin outcomes pending.

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