Ciprofloxacin (INN) is a synthetic chemotherapeutic antibiotic of the fluoroquinolone drug class [2][3] It is a second-generation fluoroquinolone antibacterial. It kills bacteria by interfering with the enzymes that cause DNA to rewind after being copied, which stops DNA and protein synthesis.
Ciprofloxacin is marketed worldwide with over three hundred different brand names. In the United States, Canada, and the UK, it is marketed as Baycip, Ciloxan, Ciflox, Cipro, Cipro XR, Cipro XL, Ciproxin and most recently, Proquin. In addition, ciprofloxacin is available as a generic drug under a variety of different brand names and is also available for limited use in veterinary medicine.
Ciprofloxacin was first patented in 1983 by Bayer A.G. and subsequently approved by the United States Food and Drug Administration (FDA) in 1987. Ciprofloxacin has 12 FDA-approved human uses and other veterinary uses, but it is often used for non-approved uses (off-label). Ciprofloxacin interacts with other drugs, herbal and natural supplements, and thyroid medications.[4]

The patent history for ciprofloxacin makes reference to a 1982 European Patent (patent number 0049355), as well a German patent dated 21 January 1986. Bayer introduced ciprofloxacin in 1987 and was later approved by the U.S. FDA on 22 October 22 1987 for use in the United States to treat specific bacterial infections. In 1991, the intravenous formulation was introduced. The current United States patent appears to be held by Bayer, being the assignee.[5] The United States patent was applied for in January 1987, but was not approved until 1996 according to the patent history.
In 2004, ciprofloxacin and levofloxacin together commanded 65% ($3.3 billion) of the global sales of the fluoroquinolone class.[6] The first nine months of 2008 sales for ciprofloxacin were $242 million, as compared to $324 million for Bayer aspirin.[7] Ciprofloxacin has proven to be a blockbuster drug for Bayer A. G., generating billions of dollars in additional revenue. “In 1999, Cipro was the eleventh most prescribed drug in the United States based on new prescriptions, and ranked twentieth in total United States sales. In 1999, Bayer’s gross sales of Cipro in the United States were approximately $1.04 billion.”[8] The sale of ciprofloxacin increased dramatically following the anthrax scare of 2001. On 24 October 2002, the Bush Administration (2001–2009) announced a deal between the government and Bayer Pharmaceuticals to purchase 100 million tablets of ciprofloxacin at a reduced price of $0.95 per pill. A full course of ciprofloxacin for postexposure prophylaxis (60 days) resulting from this arrangement costs the government $204 per person treated, compared with $12 per person treated with doxycycline, the drug normally used to treat anthrax, a difference of $192.[9]

•Generic equivalents:
On 24 October 2001, The Prescription Access Litigation (PAL), filed suit to dissolve an agreement between Bayer, Barr Laboratories, and two other generic drug companies that it claimed was blocking access to adequate supplies and cheaper, generic versions of ciprofloxacin. The plaintiffs charged that Bayer Corporation, a unit of Bayer AG, had unlawfully paid three of its competitors — Barr Laboratories, Rugby, and Hoechst-Marion Roussel — a total of $200 million to prevent cheaper, generic versions of ciprofloxacin from being brought to the market, as well as manipulating the price and supply of ciprofloxacin. Numerous other consumer advocacy groups joined this lawsuit. On 15 October 2008, five years after Bayer’s patent had expired, the United States District Court for the Eastern District of New York granted Bayer’s and the generic defendants’ motion for summary judgment, holding that any anticompetitive effects caused by the settlement agreements between Bayer and the generic defendants were within the exclusionary zone of the patent, and thus could not be redressed by federal antitrust law,[10] in effect upholding Bayer’s agreement to pay Barr Laboratories, Rugby, and Hoechst-Marion Roussel a total of $200 million to prevent the marketing a generic equivalent of ciprofloxacin.


Ciprofloxacin is available as:

•tablets (250 mg, 500 mg or 750 mg)
•intravenous solutions (5% and 10%, 100 mL)
•eye and ear drops
In most countries, all formulations require a prescription.

See the latest package insert for ciprofloxacin (Cipro) for additional details.[39]
Mode of action:
Ciprofloxacin is a broad-spectrum antibiotic that is active against both Gram-positive and Gram-negative bacteria. It functions by inhibiting DNA gyrase, a type II topoisomerase, and topoisomerase IV,[40] enzymes necessary to separate bacterial DNA, thereby inhibiting cell division.
This mechanism can also affect mammalian cell replication. In particular, some congeners of this drug family (for example those that contain the C-8 fluorine)[41] display high activity not only against bacterial topoisomerases but also against eukaryotic topoisomerases and are toxic to cultured mammalian cells and in vivo tumor models.[42] Although quinolones are highly toxic to mammalian cells in culture, its mechanism of cytotoxic action is not known. Quinolone induced DNA damage was first reported in 1986 (Hussy et al.).[43]
Recent studies have demonstrated a correlation between mammalian cell cytotoxicity of the quinolones and the induction of micronuclei.[44][45][46][47] As such some fluoroquinolones may cause injury to the chromosome of eukaryotic cells.[48][49][50][51][52][53]
There continues to be debate as to whether or not this DNA damage is to be considered one of the mechanisms of action concerning the severe adverse reactions experienced by some patients following fluoroquinolone therapy.[42][54][55]

Adverse effects:
Serious adverse events occur more commonly with fluoroquinolones than with any other antibiotic drug classes. In most, adverse reactions are mild to moderate; however, occasionally serious adverse effects occur.[64][65] There have been a number of regulatory actions taken as a result of such adverse reactions, which included published warnings,[66][67] additional warnings and safety information added to the package inserts[68] together with the issuance of “Dear Doctor Letters”[69] concerning the recent addition of Black Box Warnings. In 2004, the U.S. FDA requested new warning labels to be added to all of the fluoroquinolones, including ciprofloxacin, regarding peripheral neuropathy (irreversible nerve damage), tendon damage, heart problems (prolonged QT Interval / torsades de pointes), pseudomembranous colitis, rhabdomyolysis (muscle breakdown), Stevens-Johnson syndrome, as well as concurrent usage of NSAIDs contributing to the severity of these reactions.
Subsequent to this, on June 25, 2007, the U.S. FDA required the manufacturer to add an additional warning to the package inserts that stated that “Other serious and sometimes fatal events, some due to hypersensitivity, and some due to uncertain etiology, have been reported in patients receiving therapy with quinolones, including ciprofloxacin.”[70] It was not until 2008, (four years later) that the label revisions for ciprofloxacin included any warnings concerning heart problems (prolonged QT Interval / torsades de pointes). Warnings concerning rhabdomyolysis and Stevens-Johnson syndrome are still conspicuously absent from the package inserts as of September 2009.
The serious adverse effects that may occur as a result of ciprofloxacin therapy include irreversible peripheral neuropathy,[71][72] spontaneous tendon rupture and tendonitis,[73][74][75][76] acute liver failure or serious liver injury (hepatitis),[77][78] QTc prolongation/torsades de pointes,[24] toxic epidermal necrolysis (TEN),[79][80][81] and Stevens-Johnson syndrome, severe central nervous system disorders (CNS)[30] and Clostridium difficile associated disease (CDAD: pseudomembranous colitis),[82][83] as well as photosensitivity/phototoxicity reactions.
Psychotic reactions and confusional states, acute pancreatitis,[84] bone marrow depression, interstitial nephritis and hemolytic anemia may also occur during ciprofloxacin therapy.[85][86] Additional serious adverse reactions include temporary, as well as permanent, loss of vision,[87][88] irreversible double vision,[89] drug induced psychosis[90][91] and chorea (involuntary muscle movements),[92] impaired color vision, exanthema, abdominal pain, malaise, drug fever, dysaesthesia and eosinophilia.[93][94] Pseudotumor cerebri, commonly known as idiopathic intracranial hypertension (IIH), (also referred to as increased intracranial pressure), has been reported to occur as a serious adverse reaction to ciprofloxacin.[95]
Children and the elderly are at a much greater risk of experiencing such adverse reactions.[96][97] Such reactions may manifest during fluoroquinolone therapy, and long after it had been discontinued.[98]
Serious visual complications have also been reported to occur with ophthalmic fluoroquinolone therapy, which may also occur with ciprofloxacin eye drops, especially corneal perforation, but also evisceration and enucleation. This increased incidents of corneal perforation may be due to fluoroquinolones causing alterations in stromal collagen, leading to a reduction in tectonic strength.[99][100] As noted previously permanent double vision (diplopia) has also been reported.[89] An unusual case of seizures has also been reported with ciprofloxacin ear drops in an elderly patient.[101]
Some groups refer to these adverse events as “fluoroquinolone toxicity”. These groups of people claim to have suffered serious long term harm to their health from using fluoroquinolones. This has led to a class action lawsuit by people harmed by the use of fluoroquinolones, as well as legal action by the consumer advocate group Public Citizen.[102] Partly as a result of the efforts of the State of Illinois and Public Citizen, the FDA ordered black box warnings on all fluoroquinolones advising consumers of the possible toxic effects of fluoroquinolones on tendons.[103]

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