Can fluoroquinolones be prescribed to patients with ankylosing spondylitis?

Fluoroquinolones in Ankylosing Spondylitis: Use with Extreme Caution

Fluoroquinolones can be prescribed to patients with ankylosing spondylitis when clinically necessary for bacterial infections, but this population faces significantly elevated risk of tendon complications and should be considered high-risk patients requiring careful risk-benefit assessment.

Key Risk Considerations

Ankylosing Spondylitis as a Specific Risk Factor

• Ankylosing spondylitis is explicitly listed as a potential risk factor for fluoroquinolone-associated tendon disorders 1
• Patients with AS already have underlying inflammatory joint and tendon pathology, which may compound fluoroquinolone-related musculoskeletal toxicity 1

Tendon Complication Risks

The evidence demonstrates substantial tendon-related risks with fluoroquinolones:

• Current fluoroquinolone use increases the risk of Achilles tendon rupture 4.1-fold (OR 4.1,95% CI 1.8-9.6) 1
• General tendon disorder risk increases 1.7-fold (OR 1.7,95% CI 1.4-2.0) 1
• 90% of fluoroquinolone-associated tendon disorders involve the Achilles tendon, with bilateral involvement in over half of cases 1
• Symptoms typically occur within 1 week of exposure (median 6 days), though can occur as late as 6 months after discontinuation 1

Compounding Risk Factors

If the AS patient is also taking corticosteroids, the risk escalates dramatically:

• Concomitant fluoroquinolone and corticosteroid use increases Achilles tendon rupture risk 43.2-fold (OR 43.2,95% CI 5.5-341.1) 1
• In patients over 60 years with concurrent corticosteroid use, 1 in 979 patients will experience Achilles tendon rupture 1

Age further modifies risk:

• 71% of fluoroquinolone-associated tendinopathies occur in patients older than 60 years 1
• Risk of Achilles tendon rupture is 4 times higher in persons older than 60 years compared to younger patients 1

Clinical Decision Algorithm

When infection requires antibiotic treatment in AS patients:

1. First-line approach: Select alternative antibiotics without tendon toxicity risk whenever clinically appropriate [@2-9@]

2. If fluoroquinolone is necessary (based on culture sensitivities or clinical urgency):

   • Document the specific indication and why alternatives are unsuitable
   • Avoid fluoroquinolones entirely if patient is concurrently taking systemic corticosteroids 1
   • Counsel patient about tendon pain as an early warning sign requiring immediate drug cessation 1
   • Consider shortest effective treatment duration 1
   • Advise activity modification during and for 30 days after treatment 1

3. Monitor closely: Instruct patients to stop fluoroquinolone immediately and contact provider if any tendon pain, swelling, or inflammation develops 1

Important Caveats

• 26% of patients with fluoroquinolone-associated tendon disorders still reported pain and disability at follow-up, indicating potential for permanent morbidity 1
• The absolute risk remains relatively low (12 cases per 100,000 persons within 90 days), but the relative risk increase is substantial 1
• One small open-label trial showed moxifloxacin improved AS symptoms, but this does not justify fluoroquinolone use for AS treatment given the established tendon risks and lack of guideline support 2

What Guidelines Say About AS Treatment

The 2019 ACR/SAA/SPARTAN guidelines for AS treatment do not include fluoroquinolones as therapeutic agents 1. Standard AS treatment involves NSAIDs, TNF inhibitors, IL-17 inhibitors, and JAK inhibitors—not antibiotics 1, 3.