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Azithromycin, cardiovascular risks, QTc interval prolongation, torsade de pointes, and regulatory issues: A narrative
Jules C Hancox1, Mehrul Hasnain2, W Victor R Vieweg3
1School of Physiology and Pharmacology and Cardiovascular Research Laboratories, Medical Sciences Building, University of Bristol, University Walk, Bristol, UK.
Insights
Azithromycin can prolong the QTc interval and cause fatal arrhythmias, especially in elderly women with heart disease. Risk factors include concurrent medications and electrolyte imbalances.
Area of Science:
- Cardiology
- Pharmacology
- Clinical Medicine
Background:
- Conflicting reports on azithromycin's cardiac safety, specifically QTc interval prolongation and torsade de pointes, have emerged.
- The FDA advises caution regarding azithromycin-induced arrhythmias in at-risk patients.
- A systematic review was conducted to identify factors associated with these adverse cardiac events.
Purpose of the Study:
- To determine factors linking azithromycin use to QTc interval prolongation and torsade de pointes.
- To analyze risk factors in patients experiencing azithromycin-associated cardiac arrhythmias.
Main Methods:
- Systematic review of 12 case reports involving azithromycin and cardiac events.
- Analysis of patient demographics, azithromycin dosage, QTc interval measurements, and co-existing risk factors.
Main Results:
- No significant dose-response relationship between azithromycin and QTc interval duration was found in adults without congenital long QT syndrome.
- Identified risk factors include female sex, older age, pre-existing heart disease, concurrent QTc-prolonging drugs or metabolic inhibitors, hypokalemia, and bradycardia.
- All 12 subjects had at least two additional risk factors, with elderly women with heart disease being particularly vulnerable.
Conclusions:
- Azithromycin-associated QTc interval prolongation and torsade de pointes are linked to multiple risk factors.
- Elderly women with heart disease are at a heightened risk for these serious cardiac events when taking azithromycin.
Abstract:
Over the past year, three articles have appeared in the New England Journal of Medicine describing conflicting findings about azithromycin and cardiac safety, particular azithromycin-induced QTc interval prolongation and torsade de pointes. The FDA wants healthcare providers to consider azithromycin-induced fatal cardiac arrhythmias for patients already at risk for cardiac death and other potentially arrhythmogenic cardiovascular conditions. In a systematic review of case reports we sought to determine factors that link to azithromycin-induced/associated QTc interval prolongation and torsade de pointes. We found 12 cases: seven female and five male. Of the nine adults with reported azithromycin doses, concurrent QTc interval measurement, and without congenital long QT syndrome, we found no significant relationship between dose and QTc interval duration. Additional risk factors were female sex, older age, heart disease, QTc interval prolonging drugs and metabolic inhibitors, hypokalemia, and bradycardia. All 12 subjects had at least two additional risk factors. Elderly women with heart disease appear to be at particularly risk for drug-related QTc interval prolongation and torsade de pointes.
