ATC Code J01MA02, S01AE03, S02AA15, S03AA07
Formula C17H18FN3O3
Molar Mass (g·mol−1) 331,34
Physical State solid
Melting Point (°C) 318–320
PKS Value 6,09
CAS Number 85721-33-1
PUB Number 2764
Drugbank ID DB00537
Solubility moderate in water / poor in ethanol


Ciprofloxacin is an antibiotic from the group of gyrase inhibitors and fluoroquinolones that is used to treat a number of bacterial infections. These include bone and joint infections, intra-abdominal infections, certain types of infectious diarrhea, respiratory infections, skin infections, typhoid fever, and urinary tract infections. For some infections, it is used in combination with other antibiotics. It can be taken by mouth, as eye drops, as ear drops, or intravenously. Ciprofloxacin is available by prescription only.



Ciprofloxacin is a second-generation fluoroquinolone active against many Gram-negative and Gram-positive bacteria. It exerts its effects by inhibiting bacterial DNA gyrase and topoisomerase IV. Ciprofloxacin binds to bacterial DNA gyrase with 100-fold higher affinity of mammalian DNA gyrase. Binding to bacterial gyrase prevents its supercoiling of DNA and thus prevents DNA replication. This prevents the bacteria from further dividing and replicating.


The bioavailability is about 70%. The maximum plasma concentration is reached after one hour. Plasma protein binding is around 20-40%. There is little available data on the enzymes and types of reactions involved in the metabolism of ciprofloxacin. Ciprofloxacin is excreted approximately 45% in urine and approximately 55% in feces. The plasma half-life is about


Side effects

There is an increased risk of tendonitis and tendon rupture, especially in persons older than 60 years, in persons using additional corticosteroids, and in persons with kidney, lung, or heart transplants.

Fluoroquinolones, including ciprofloxacin, are associated with an increased risk of cardiac toxicity, including QT interval prolongation, torsades de pointes, ventricular arrhythmia, and sudden cardiac death.

Fluoroquinolones can induce seizures or lower seizure thresholds, and may also cause other adverse effects on the central nervous system. Headache, dizziness, and insomnia are relatively common with use.

Toxicological Data

LD50 (rat, oral): > 2000 mg-kg-1


  • Drugbank
  • PubChem
  • Aktories, Förstermann, Hofmann, Starke: Allgemeine und spezielle Pharmakologie und Toxikologie, Elsvier, 2017
Markus Falkenstätter

Markus Falkenstätter

Markus Falkenstätter ist Autor zu pharmazeutischen Themen in der Medizin-Redaktion von Medikamio. Er befindet sich im letzten Semester seines Pharmaziestudiums an der Universität Wien und liebt das wissenschaftliche Arbeiten im Bereich der Naturwissenschaften.

Mag. pharm Stefanie Lehenauer

Mag. pharm Stefanie Lehenauer

Stefanie Lehenauer ist seit 2020 freie Autorin bei Medikamio und studierte Pharmazie an der Universität Wien. Sie arbeitet als Apothekerin in Wien und ihre Leidenschaft sind pflanzliche Arzneimittel und deren Wirkung.

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