From the Guidelines
Antibiotics, particularly macrolides, can have significant cardiovascular effects, and caution is warranted in patients with pre-existing cardiac conditions or those taking other QT-prolonging medications. Macrolides, such as azithromycin, erythromycin, and clarithromycin, have been associated with cardiac arrhythmias, including QT interval prolongation, which can lead to life-threatening conditions like Torsades de Pointes 1. The mechanism behind QT prolongation involves blockade of potassium channels in cardiac cells, delaying ventricular repolarization. Factors increasing the risk of malignant arrhythmias with macrolides include age >80, female gender, heart disease, use of other QT prolonging medication, reduced drug elimination, bradycardia, prolonged QT interval before therapy, and genetic predisposition 1.
Some key points to consider when prescribing antibiotics with potential cardiovascular effects include:
- Monitoring ECGs before and during treatment with high-risk antibiotics is recommended for vulnerable patients 1
- Any symptoms like palpitations, dizziness, or syncope during antibiotic therapy should prompt immediate medical attention
- Alternative antibiotics like penicillins, cephalosporins, or tetracyclines may be safer options for high-risk patients as they have minimal cardiac effects
- The risk of cardiovascular death associated with macrolide use is rare, but still a concern, especially in patients with high baseline risk and comorbidity 1
In the context of long-term macrolide use, the British Thoracic Society guideline reports that the recognized side-effect profile associated with macrolide therapy includes cardiac arrhythmias and QTc prolongation, although these events are rare 1. Therefore, it is essential to weigh the benefits and risks of antibiotic use and consider alternative options for patients at high risk of cardiovascular complications.
From the FDA Drug Label
Cardiovascular: Palpitations, chest pain. Cardiovascular: Chest pain Cardiovascular: Arrhythmias including ventricular tachycardia and hypotension There have been rare reports of QT prolongation and torsades de pointes.
Cardiovascular Effects of Azithromycin:
- Palpitations and chest pain have been reported in patients taking azithromycin 2 2.
- Arrhythmias, including ventricular tachycardia and hypotension, have been reported in post-marketing experience with azithromycin 2 2.
- Rare reports of QT prolongation and torsades de pointes have also been associated with azithromycin 2 2. It is essential to exercise caution when prescribing azithromycin to patients with pre-existing cardiovascular conditions or those who are at risk of developing cardiovascular complications.
From the Research
Cardiovascular Effects of Antibiotics
- The use of antibiotics in patients with cardiovascular disease requires careful consideration of their potential effects on the cardiovascular system 3.
- Some studies have suggested that antibiotics may increase the risk of cardiovascular events and mortality, particularly in patients with established coronary heart disease 4.
- A systematic review of 38 trials found that antibiotics, including macrolides and quinolones, may increase the risk of all-cause mortality, cardiovascular mortality, and stroke in patients with coronary heart disease 4.
Antibiotic Treatment of Community-Acquired Pneumonia
- The treatment of community-acquired pneumonia (CAP) with antibiotics is a common practice, and the choice of antibiotic regimen can have a significant impact on patient outcomes 5, 6, 7.
- A systematic review of 20 studies found that antibiotic therapy consisting of β-lactam plus macrolide combination therapy or fluoroquinolone monotherapy initiated within 4 to 8 hours of hospital arrival was associated with lower adjusted short-term mortality in adults hospitalized with CAP 7.
- However, the optimal choice of antibiotic regimen for CAP remains unclear, and further research is needed to determine the most effective treatment strategies 6.
Potential Harms of Antibiotics
- The use of antibiotics, particularly macrolides and quinolones, has been associated with an increased risk of cardiovascular events and mortality in some studies 4.
- A systematic review found that antibiotics may increase the risk of all-cause mortality, cardiovascular mortality, and stroke in patients with coronary heart disease, and that the current evidence does not support the clinical use of macrolides and quinolones for the secondary prevention of coronary heart disease 4.
- Further research is needed to fully understand the potential harms of antibiotics and to determine the most effective and safe treatment strategies for patients with cardiovascular disease 4.