Tendon problems
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. Cardiac arrhythmia
The fluoroquinolones, including ciprofloxacin, are associated with an increased risk of cardiac toxicity, including QT interval prolongation, torsades de pointes, ventricular arrhythmia, and sudden death. Nervous system
Because Ciprofloxacin is lipophilic, it has the ability to cross the blood-brain barrier. The 2013 FDA label warns of nervous system effects. Ciprofloxacin, like other fluoroquinolones, is known to trigger seizures or lower the seizure threshold, and may cause other central nervous system adverse effects. Headache, dizziness, and insomnia have been reported as occurring fairly commonly in postapproval review articles, along with a much lower incidence of serious CNS adverse effects such as tremors, psychosis, anxiety, hallucinations, paranoia, and suicide attempts, especially at higher doses. Like other fluoroquinolones, it is also known to cause peripheral neuropathy that may be irreversible, such as weakness, burning pain, tingling or numbness.
The European Association of Urology recommends ciprofloxacin as an alternative regimen for the treatment of uncomplicated urinary tract infections, but cautions that the potential for "adverse events have to be considered".Although approved by regulatory authorities for the treatment of respiratory infections, ciprofloxacin is not recommended for respiratory infections by most treatment guidelines due in part to its modest activity against the common respiratory pathogen Streptococcus pneumoniae. "Respiratory quinolones" such as levofloxacin, having greater activity against this pathogen, are recommended as first line agents for the treatment of community-acquired pneumonia in patients with important co-morbidities and in patients requiring hospitalization (Infectious Diseases Society of America 2007). Similarly, ciprofloxacin is not recommended as a first-line treatment for acute sinusitis.Ciprofloxacin is approved for the treatment of gonorrhea in many countries, but this recommendation is widely regarded as obsolete due to resistance development. Pregnancy
In the United States ciprofloxacin is pregnancy category C. This category includes drugs for which no adequate and well-controlled studies in human pregnancy exist, and for which animal studies have suggested the potential for harm to the fetus, but potential benefits may warrant use of the drug in pregnant women
despite potential risks. An expert review of published data on experiences with ciprofloxacin use during pregnancy by the Teratogen Information System concluded therapeutic doses during
pregnancy are unlikely to pose a substantial teratogenic risk (quantity and quality of data=fair), but the data are insufficient to state no risk exists.