The black box warning on the . FDA-approved ciprofloxacin label warns of 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 drug.  A case control study  performed using a UK medical care database found that fluoroquinolone use was associated with a -fold increase in tendon problems. The relative risk increased to in those over 60 years of age and to in those over the age of 60 who were also taking corticosteroids. Among the 46,766 quinolone users in the study, 38 (%) cases of Achilles tendon rupture were identified. A study performed using an Italian healthcare database reached qualitatively similar conclusions.