Home Medicines Ciprofloxacin: effect, areas of application, side effects

Ciprofloxacin: effect, areas of application, side effects

by Josephine Andrews
Published: Last Updated on 277 views

Ciprofloxacin is a synthetic antibiotic. Its bactericidal effect is used for numerous applications. These include intestinal, bile duct and urinary tract infections as well as meningitis. Due to the risk of side effects, which can also be long-lasting and possibly even irreversible, great caution is recommended when using the antibiotic. Read everything you need to know about ciprofloxacin here.

How ciprofloxacin works

Ciprofloxacin is an antibiotic agent from the group of fluoroquinolone antibiotics (old name: gyrase inhibitor). It has a bactericidal (bactericidal) effect on sensitive pathogens:

Ciprofloxacin blocks bacteria from multiplying by reducing their ability to make new genetic material (DNA) and cell division. It inhibits several important enzymes : topoisomerase II (DNA gyrase) and topoisomerase IV.

These enzymes temporarily break down the bacterial genetic material in order to transform it from its extremely compact structure (superhelix) into a relaxed form. Only then can it be duplicated, which is necessary before cell division, so that each of the two daughter cells that are created then has a complete set of the genetic material.

By inhibiting the two enzymes mentioned and thus the “breaking up” of the bacterial DNA, ciprofloxacin prevents the division and proliferation of the bacterial cell.

The exact mechanism of action and other effects of ciprofloxacin and other gyrase inhibitors have not yet been clarified and are currently being researched. This also includes the so-called post-antibiotic effect (the effect of the antibiotic persists even though it is no longer administered).

intake, degradation and excretion

More than 90 percent of ciprofloxacin is absorbed in the small intestine after it has been taken by mouth (orally). In the body, it is distributed both extracellularly (outside the cells) and intracellularly (inside the cells), which is why it is also effective against some atypical pathogens.

The antibiotic is broken down mainly in the liver, excretion via the kidneys and the stool. About three to five hours after ingestion, half of the active ingredient has left the body (half-life).

When is ciprofloxacin used?

Ciprofloxacin shows high activity against gram-negative bacteria. However, it can also be used against gram-positive pathogens and against those that infiltrate the body’s cells.

There are currently numerous areas of application. On the one hand, the antibiotic acts against many different infectious diseases such as intestinal diseases or bile duct and abdominal cavity infections, provided that a pathogen sensitive to ciprofloxacin is responsible.

On the other hand, the active ingredient is used as a reserve antibiotic for urinary tract infections. This means that due to severe side effects, especially in children and adolescents, therapy with ciprofloxacin is only resorted to if the disease is very severe and other therapies are not sufficiently effective.

Anthrax and pneumonia caused by legionella can also be treated with the active ingredient. In contrast, therapy with ciprofloxacin makes less sense in classic pneumonia. The reason: the antibiotic is only weakly effective against pneumococcal bacteria, which are most commonly responsible for common pneumonia (“pneumococcal gap”).

If there is a family history of meningococcal meningitis (an inflammation of the meninges caused by meningococcal bacteria), ciprofloxacin is given to family members as a preventative measure so that they do not also become ill.

Ciprofloxacin is also used for local infections in the eyes or ears in the form of eye and ear drops. Since, in contrast to aminoglycoside antibiotics (e.g. gentamicin), it has no hearing-damaging (ototoxic) effect, it can also be used on perforated eardrums .

How Ciprofloxacin is used

The drug can be administered in various dosage forms. These are – like the dosage – strongly dependent on the disease to be treated and the pathogen responsible for it.

A common form of administration is the oral form: the active substance is administered as tablets (usually in a dosage of 250 or 500 mg per tablet). It must be taken at about the same time every day to ensure a sufficient concentration of the active ingredient in the body. The tablets must not be chewed – they must be swallowed whole.

It is taken independently of meals (before, with or after meals). When taken on an empty stomach, the active ingredient usually enters the blood faster.

Ciprofloxacin must not be taken with dairy products or calcium-rich foods as this will prevent it from being absorbed into the body.

Other dosage forms are also available, for example preparations for intravenous administration or eye and ear drops with ciprofloxacin.

Usually the antibiotic is applied twice a day. However, the instructions of the doctor or pharmacist must be followed.

What are the side effects of ciprofloxacin?

Treatment with ciprofloxacin can have various side effects. Among the most observed are nausea, diarrhea and skin rashes.

The structure of tendons and tendon attachments can also change as a result of the use of ciprofloxacin. As a result, inflammation and tears can occur in the tendon area, especially in the Achilles tendon area. Patients who are over 60 years old, have an organ transplant or are being treated with glucocorticoids (“cortisone”) at the same time are particularly susceptible to tendinitis and tears caused by ciprofloxacin.

Ciprofloxacin can also cause central nervous system disorders. These include, for example, sensory disturbances, dizziness and tiredness.

Side effects on the musculoskeletal system and nervous system may be long-lasting and possibly irreversible. Ciprofloxacin (and other fluoroquinolones) should therefore only be used when absolutely necessary. If you develop symptoms such as tendinitis, muscle weakness, muscle or joint pain, joint swelling, or sensory disturbances during treatment, you should stop taking the antibiotic immediately and tell your doctor.

Furthermore, ciprofloxacin can lengthen the so-called QT interval in the heart. Appropriate caution is therefore required if the patient is also receiving other drugs with a QT interval-prolonging effect (e.g. citalopram) or has a congenital QT interval disorder.

Rarely, ciprofloxacin can increase the sensitivity of the skin to sunlight (phototoxicity). Sensitive people (including light skin types) should therefore ensure adequate sun protection while taking it.

What should be considered when using ciprofloxacin?


Ciprofloxacin must not be used together with the active substance tizanidine (a centrally acting muscle relaxant = muscle relaxant).


Like other antibiotics, antibiotics such as ciprofloxacin must be used without interruption for the entire period prescribed by the doctor. The application must not be discontinued prematurely even if the symptoms of the disease have already disappeared. Otherwise, the infection can break out again and then be even more difficult to treat because the pathogens remaining in the body were able to adapt to the active substance. Experts speak of a development of resistance.

Drugs and foods that contain many multiply charged metal ions can form complexes with ciprofloxacin, reducing the effectiveness of the drug. Therefore, for example, the consumption of dairy products should be avoided for the duration of the treatment.

Since the active ingredient in the brain lowers the seizure threshold, it must be used with great caution in patients suffering from seizures (epilepsy).

Ciprofloxacin is an inhibitor of the enzyme CYP1A2. The effect of drugs that are broken down via CYP1A2 can therefore be enhanced by ciprofloxacin. These include:

  • theophylline (used to treat asthma and COPD) and caffeine
  • Duloxetine and agomelatine (antidepressants)
  • Clozapine (antipsychotic)
  • Cyclosporine (immunosuppressant)
  • Ropinirole (medicine against Parkinson’s disease and restless legs syndrome )
  • glibenclamide (medicine for diabetes)
  • Phenytoin (antiepileptic)
  • zolpidem (sleeping pills)

Ability to drive and operate heavy machinery

Impaired reactions, especially when driving or operating machines, are temporary side effects of therapy with ciprofloxacin.

Alcohol intensifies these phenomena. Therefore, avoid alcohol while taking ciprofloxacin.

age restriction

Ciprofloxacin can also be given to children and adolescents in severe infections. The dosage is generally determined based on the pathogen, kidney function and body weight.

pregnancy and breast feeding period

Data on gyrase inhibitors with over 1000 exposed pregnant women did not show an increased risk of malformations. Ciprofloxacin is therefore an antibiotic of second choice during pregnancy. If more suitable alternatives (penicillins, cephalosporins, macrolides) are not an option or do not work, it can be used. Local treatment (eye and ear drops) is acceptable.

To date, no evidence of ciprofloxacin has been found in the plasma of breastfed children whose mothers have taken the drug while breastfeeding. In individual cases, the babies can get a thinner stool.

As in pregnancy, penicillins, cephalosporins and macrolides should also be preferred during breastfeeding. However, if therapy with ciprofloxacin is necessary, you can breastfeed while you are taking it.

How to get Ciprofloxacin medication

Ciprofloxacin requires a prescription in Germany, Austria and Switzerland. It may only be used as directed by a doctor.

The ciprofloxacin eye ointment available in Austria and Switzerland is not commercially available in Germany. Conversely, the ciprofloxacin juices available in Germany and Switzerland are not registered in Austria.

Since when is ciprofloxacin known?

The active ingredient was developed in 1981 and is therefore still relatively young. Since the patent expired, numerous ciprofloxacin preparations have come onto the market in a wide variety of dosage forms.

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