Antibiotic-induced cardiac arrhythmias

Area of Science:

• Pharmacology
• Cardiology
• Clinical Medicine

Background:

• Macrolides and fluoroquinolones are widely used antibiotics.
• These drugs carry a rare risk of Torsades de pointes (TdP), a potentially fatal arrhythmia.
• The mechanism involves prolongation of the cardiac action potential and dispersion of repolarization.

Purpose of the Study:

• To clarify the risk of arrhythmia associated with macrolide and fluoroquinolone antibiotics.
• To identify factors that predispose patients to TdP when using these antibiotics.

Main Methods:

• Review of existing literature on macrolide/fluoroquinolone use and cardiac events.
• Analysis of the electrophysiological effects of these antibiotics on cardiac repolarization.
• Identification and categorization of risk factors for TdP.

Main Results:

• Macrolides and fluoroquinolones can prolong the QTc interval, increasing TdP risk.
• Potency as potassium channel blockers is low, with minimal inter-drug differences.
• Impaired cardiac repolarization (congenital or acquired) is a prerequisite for TdP.
• Key risk factors include prolonged baseline QTc, Class III antiarrhythmics, hypokalemia, hypomagnesemia, drug interactions, and bradycardia.

Conclusions:

• The incidence of TdP is very low in the absence of major risk factors.
• Correcting modifiable risk factors is crucial for patient safety.
• Antibiotic use should not be altered for most patients due to the rare risk of TdP, except in high-risk individuals.