What antibiotics are contraindicated in patients with aortic dissection?

Antibiotics Contraindicated in Aortic Dissection

Fluoroquinolones should be avoided in patients with aortic dissection or those at high risk for aortic disease unless no alternative antibiotics exist, and antithrombotic therapy (anticoagulation and antiplatelet agents) must be withheld in suspected aortic dissection. 1, 2

Fluoroquinolone Contraindication

Evidence for Avoidance

• The European Society of Cardiology recommends avoiding fluoroquinolones unless there is a compelling indication with no alternative available in patients with aortic aneurysm or dissection. 1
• Fluoroquinolone use is associated with a 2.11-fold increased combined risk of aortic aneurysm and dissection compared to control antibiotics, with specific risks of 2.83 for aneurysm and 1.99 for dissection. 3
• A large US population study demonstrated a 34% increased risk (aHR 1.34) of aortic aneurysm or dissection with fluoroquinolone use compared to macrolides, with the association primarily driven by aortic aneurysm cases (95.8%). 4
• All three major fluoroquinolones (ciprofloxacin, levofloxacin, and moxifloxacin) are associated with aortic aneurysm based on FDA adverse event reporting data, with oral administration carrying higher risk. 5

Conflicting Evidence

• One recent 2025 nested case-cohort study with animal models found no association between fluoroquinolone exposure and increased AA/AD hazard ratios, even in high-risk populations (elderly ≥65 years, hypertensive, prevalent aortic disease). 6
• Despite this single contradictory study, the weight of evidence from multiple large epidemiological studies and guideline recommendations supports avoidance when alternatives exist.

Clinical Application

• If fluoroquinolones are absolutely necessary (e.g., multidrug-resistant organisms with no other options), use the shortest effective duration and ensure close monitoring. 7
• Preferred alternatives include beta-lactams, aminoglycosides, or other antibiotic classes depending on the infection source and susceptibility patterns. 2

Antithrombotic Therapy - Mandatory Withholding

Anticoagulation

• Withholding antithrombotic therapy in suspected aortic dissection is mandatory until the diagnosis is excluded. 2, 1
• The European Society of Cardiology explicitly states that anticoagulation or dual antiplatelet therapy (DAPT) should not be used routinely in patients with aortic aneurysms, as these agents provide no benefit and significantly increase bleeding risk. 1
• Intra-aortic balloon counterpulsation is absolutely contraindicated in acute aortic dissection. 2

Beta-Blockers - Use with Extreme Caution

• Beta-blockers should be used very cautiously, if at all, in acute aortic regurgitation (a common complication of aortic dissection) because they block the compensatory tachycardia needed to maintain cardiac output. 2
• However, intravenous beta-blockers are first-line agents for blood pressure and heart rate control in confirmed aortic dissection without severe acute regurgitation, targeting heart rate ≤60 bpm and systolic BP <120 mmHg. 8

Management Priorities in Suspected Aortic Dissection

Initial Treatment Approach

• Treatment should be limited to pain relief and blood pressure control in suspected aortic dissection. 2
• Intravenous beta-blockers (labetalol or esmolol) should be initiated first to reduce the force of left ventricular ejection. 8
• If beta-blockers alone are insufficient, add intravenous vasodilators such as calcium channel blockers or nitrates. 8
• Never use vasodilators alone without prior beta-blockade, as this increases aortic wall stress through reflex tachycardia. 8

Diagnostic Considerations

• The ADD score should be used in the pre-hospital and emergency setting to assess probability of aortic dissection. 2
• Focused cardiac ultrasound (FoCUS) echocardiography may support the diagnosis. 2

Common Pitfalls to Avoid

• Do not prescribe fluoroquinolones for routine infections (UTI, pneumonia, sinusitis) in patients with known aortic disease or risk factors (hypertension, connective tissue disorders, bicuspid aortic valve, family history). 1, 7
• Do not continue anticoagulation or antiplatelet therapy when aortic dissection is suspected - this is a mandatory withholding. 2, 1
• Do not use dihydropyridine calcium channel blockers without beta-blockers due to reflex tachycardia risk. 8
• Do not delay beta-blocker administration when managing confirmed aortic dissection, as controlling dP/dt is crucial to prevent propagation. 8