Also Known As: Norfloxacin, Noroxin, Chibroxin
Norfloxacin is a synthetic chemotherapeutic antibacterial agent occasionally used to treat common as well as complicated urinary tract infections. It is sold under various brand names with the most common being Noroxin. In form of ophthalmic solutions it is known as Chibroxin. Norfloxacin is a first generation synthetic fluoroquinolone (quinolone) developed by Kyorin Seiyaku K.K. (Kyorin).
The licensed uses for norfloxacin are quite limited as norfloxacin is to be considered a drug of last resort when all other antibiotics have failed. There are currently only three approved uses in the adult population (one of which is restricted) and the other ineffective due to bacterial resistance. Chibroxin (ophthalmic) is approved for use in children older than one year of age.
Norfloxacin interacts with a number of other drugs, as well as a number of herbal and natural supplements. Such interactions increase the risk of anticoagulation and the formation of non-absorbable complexes, as well as increasing the risk of toxicity.
Norfloxacin is associated with a number of serious and life threatening adverse reactions as well as spontaneous tendon ruptures and irreversible peripheral neuropathy. Such reactions may manifest long after therapy had been completed and in severe cases may result in lifelong disabilities. Hepatoxicity resulting in fatalities has also been reported with the use of norfloxacin.
In the adult population Oral and I.V. Norfloxacin is limited to the treatment of proven bacterial infections. The initial approval by the U.S. Food and Drug Administration (FDA) in 1986 encompassed the following indications:
- Uncomplicated urinary tract infections (including cystitis)
- Complicated urinary tract infections (restricted use) 
- Uncomplicated urethral and cervical gonorrhea (however this indication is no longer considered to be effective by some experts due to bacterial resistance) 
- Prostatitis due to Escherichia coli.
- Syphilis treatment: Norfloxacin has not been shown to be effective in the treatment of syphilis. Antimicrobial agents used in high doses for short periods of time to treat gonorrhea may mask or delay the symptoms of incubating syphilis.
Though the fluoroquinolones are sometimes used to treat typhoid and paratyphoid fever, it should be noted here that norfloxacin had more clinical failures than the other fluoroquinolones (417 participants, 5 trials).
In ophthalmology, Norfloxacin licensed use is limited to the treatment of conjunctival infections caused by susceptible bacteria.
Norfloxacin has been restricted in the Republic of Ireland due to the risks of C. difficile super infections and permanent nerve as well as tendon injuries. It licensed use in acute and chronic complicated kidney infections has been withdrawn as a result.
The European Medicines Agency, also in 2008, had recommended restricting the use of oral norfloxacin to treat urinary infections. CHMP had concluded that the marketing authorizations for norfloxacin, when used in the treatment of acute or chronic complicated pyelonephritis, should be withdrawn because the benefits do not outweigh their risks in this indication. CHMP stated that doctors should not prescribe oral norfloxacin for complicated pyelonephritis and should consider switching patients already taking oral norfloxacin for this type of infection to an alternative antibiotic.
Note: Norfloxacin may be licensed for other uses, or restricted, by the various regulatory agencies worldwide.