Incorporation of labeled deoxynucleoside triphosphates into mtDNA by isolated rat liver mitochondria has been shown previously to reflect DNA replication. We have used this system to seek evidence for a mtDNA gyrase. Coumermycin, novobiocin, nalidixic acid, and oxolinic acid are known to be inhibitors of Escherichia coli gyrase, to inhibit E. coli DNA replication, to abolish colicin E1 replication, and to depress the supercoiling of phage lambda DNA, the last two via inhibition of the DNA gyrase.

Of the 712 [pediatric] subjects evaluable for safety, 275 (52%) levofloxacin-treated subjects experienced one or more adverse event... Serious adverse events were reported in 33 (6%) levofloxacin-treated subjects...Two serious adverse events in levofloxacin-treated subjects resulted in fatal outcomes.

We observed ultrastructural changes in rat tendons several months after a single oral dose of a fluoroquinolone. I have no doubt what we found in rats corresponds to the clinical symptoms observed in patients during [fluoroquinolone] treatment.

We report two cases of tendon rupture associated with ciprofloxacin. One patient had a complete rupture of an Achilles tendon 6 months after taking the medication. The other case involved a partial rupture of the subscapularis tendon. Both ruptures occurred with minimal mechanical stress on the tendons, suggesting that the fluoroquinolone increased the susceptibility to rupture...

Of 100 total patients, 81 received an FQ for an inappropriate indication. Of these cases, 43 (53%) were judged inappropriate because another agent was considered first line, 27 (33%) because there was no evidence of infection based on the documented evaluation, and 11 (14%) because of inability to assess the need for antimicrobial therapy. Although the prevalence of inappropriate use was similar across various clinical scenarios, there was a borderline significant association between the hospital in which the ED was located and inappropriate FQ use.