Active Ingredients

Norfloxacin – Effect, Application & Risks


Norfloxacin is a bactericidal active ingredient that is used in human medicine in some broad-spectrum antibiotics and belongs to the group of so-called gyrase inhibitors. Norfloxacin and other members of this drug group kill bacteria by inhibiting their enzyme gyrase. Preparations that mainly or exclusively contain norfloxacin are used, among other things, for the treatment of acute infections of the urinary tract (e.g. cystitis ).

What is norfloxacin?

Due to its effect and other properties, norfloxacin is an antibiotic . The substance achieves its effect by inhibiting the bacteria’s own enzyme gyrase. This is vital for the bacteria because it is essentially responsible for the so-called DNA supercoilling.

Norfloxacin therefore belongs to the active substance class of gyrase inhibitors. Also part of this class of drugs are the closely related antibiotics levofloxacin and ofloxacin . In addition, norfloxacin is also assigned to the substance class of fluoroquinolones .

Preparations containing norfloxacin as the active ingredient are prescribed to treat acute or chronic urinary tract infections. The colorless to pale yellow active substance is usually prescribed in the form of film-coated tablets and is taken orally by the patient. In chemistry and pharmacology, norfloxacin is described by the molecular formula C 16 – H 18 – F – N 3 – O 3 . This corresponds to a moral mass of 319.33 g/mol.

Pharmacological action

Norfloxacin has a strong bactericidal effect. It follows that it kills infectious bacteria in a targeted and efficient manner. Typical of the drug class of gyrase inhibitors, norfloxacin causes an inhibition (inhibition) of the enzyme gyrase. This is a protein that is produced by the infectious bacteria themselves. They need it to shape the spatial orientation of their DNA.

Due to the immense importance of gyrase for DNA supercoiling (ring-shaped formation of the DNA), bacteria are not viable for long after the completed inhibition. They can no longer reproduce and die.

Since norfloxacin is particularly effective against bacteria that cause infections of the urinary tract or gonorrhea (colloquially “clap”), the antibiotic is mainly used in this area.

The active ingredient is usually used in monopreparations (drugs that rely on an active ingredient). Norfloxacin is rapidly absorbed from the gastrointestinal tract . It is then 25% present in plasma proteins and has a half-life of between 5 and 7 hours. Due to the physical properties of norfloxacin, it is possible for an opiate test to give a false positive result.

Medical Application & Use

Norfloxacin is considered a broad-spectrum antibiotic. It is therefore able to kill a large number of different bacteria in a highly effective manner. Due to its property as an antibiotic of the class of gyrase inhibitors, norfloxacin is used to treat infectious diseases . There is an indication for complicated and uncomplicated, chronic or acute infections of the urinary tract.

The drug can be used on both the upper and lower urinary tract. However, complicated inflammation of the renal pelvis and inflammation of the kidneys themselves (complicated pyelonephritis) are excluded . Because the European Medicines Agency and the German Federal Institute for Drugs and Medical Devices changed their benefit-risk assessment in 2009 so that there is no longer an indication for these diseases. The reason given was insufficient evidence of effectiveness in complicated pyelonephritis or inflammation of the renal pelvis.

However, there is still an indication for infections of the urinary tract that occur in connection with surgical or urological interventions. Norfloxacin is also administered for kidney stones . Other typical areas of application for the antibiotic include cystitis in women, bacterial gastroenteritis and gonorrhea.

Norfloxacin may also be prescribed to prevent possible blood poisoning that could develop with granulocytopenia . Norfloxacin is usually taken orally. The antibiotic is sold in tablet form and requires a prescription and pharmacy.

Risks & side effects

Norfloxacin must not be taken if there is a hypersensitivity ( allergy ) to the active ingredient. There is also a contraindication in the case of allergies to other drugs of the same class (quinolo antibiotics, e.g. levofloxacin, moxifloxacin , ciprofloxacin , or ofloxacin). This means that the drug must not be taken from a medical point of view because there is a contraindication.

Such is also the case with pregnant women , children and adolescents as well as during the lactation period. An application must then be omitted. Norfloxacin should not be taken even if complications of the tendons (particularly tendonitis ) have already occurred in connection with therapy with quinolo antibiotics .

Norfloxacin can cause unwanted side effects . However, this is not mandatory. Most treatments have no side effects. Studies have shown the following side effects:

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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.