Achilles tendon rupture
Ciprofloxacin includes a boxed warning in the United States due to an increased risk of tendinitis and tendon rupture, especially in people who are older than 60 years, people who also use corticosteroids, and people with kidney, lung, or heart transplants. Tendon rupture can occur during therapy or even months after discontinuation of the medication. One study found that fluoroquinolone use was associated with a 1.9-fold increase in tendon problems. The risk increased to 3.2 in those over 60 years of age and to 6.2 in those over the age of 60 who were also taking corticosteroids. Among the 46,766 quinolone users in the study, 38 (0.08%) cases of Achilles tendon rupture were identified.