Azithromycin as a cause of QT-interval prolongation and torsade de pointes in the absence of other known precipitating factors

Abstract

During treatment with azithromycin, a 55 year-old woman developed a newly prolonged QT interval and torsade de pointes in the absence of known risk factors. Female gender and acute renal failure may be considerations in patients treated with azithromycin.

Azithromycin and the Risk of Cardiovascular Death

“…This should correspond to the period of greatest risk of adverse cardiac effects, given that the case reports for azithromycin suggest an acute mechanism. [11][12][13][14][15][16][17] Because the usual duration of treatment varies according to the specific study antibiotic, we analyzed two periods: the 5-day period that is generally recommended for azithromycin and the 10-day period most commonly suggested for the other study antibiotics. The 10-day analyses for azithromycin included an interval during which patients were unlikely to be taking the drug (days 6 through 10); these days were considered separately in several analyses.…”

“…Our study was prompted by evidence that azithromycin is proarrhythmic, [11][12][13][14][15][16][17] which led us to hypothesize that it would increase the risk of sudden cardiac death. Patients who took azithromycin did have an increased risk of sudden cardiac death, as identified from a previously developed computer definition.…”

“…[8][9][10] Furthermore, accumulating evidence suggests that azithromycin also may have proarrhythmic effects. There are at least seven published reports of patients with normal baseline QT intervals in whom azithromycin had arrhythmiarelated adverse cardiac effects, including pronounced QT-interval prolongation, [11][12][13] torsades de pointes, [14][15][16] and polymorphic ventricular tachycardia in the absence of QTinterval prolongation. 17 The Food and Drug Administration's Adverse Event Reporting System includes at least 20 reports of torsades de pointes associated with azithromycin.…”

Acquired Long QT Syndrome: Frequency, Onset, and Risk Factors in Intensive Care Patients

“…56 For example, a 90-year-old woman with interstitial pneumonia and respiratory failure 53 was given penicillin (sulbactam) and azithromycin. Four hours after receiving azithromycin, the patient had a pronounced prolonged QT interval leading to a loss of consciousness associated with torsades de pointes.…”

Should Azithromycin No Longer Be Considered a Drug of Choice for Community- Acquired Pneumonia Because of Its Potential to Cause Cardiovascular Death?

“…In a recent meta-analysis, the Cochrane Collaboration analyzed randomized controlled trials involving adult patients admitted to hospital because of CAP, comparing antibiotic regimens with coverage of atypical organisms (e.g., macrolides, fluoroquinolones, tetracyclines) with regimens without atypical coverage (e.g., amoxicillin, penicillin, ceftriaxone). 5 A total of 28 trials involving 5939 patients were analyzed. Although there was an advantage in bacteriologic eradication in the arm with coverage of atypical organisms, this advantage disappeared when only high-quality studies were included in the analysis.…”