Ciprofloxacin × Dexamethasone

Additive tendon injury risk. Fluoroquinolones disrupt collagen synthesis in tendon fibres; glucocorticoids suppress repair and weaken the collagen matrix. FDA carries a boxed warning for tendinitis and Achilles tendon rupture.

Pain and swelling in the Achilles tendon (less often other large tendons: biceps, rotator cuff). Sudden 'snap' and inability to bear weight indicates rupture. Symptoms typically appear within 1–4 weeks and may persist for months after withdrawal.

Avoid the combination, especially in patients over 60, post-kidney-transplant, and with athletic activity. Alternative antibiotics: a cephalosporin or nitrofurantoin (no tendon effect). If ciprofloxacin is needed, limit physical activity for the entire course and 1 month after.