Uses and Side Effects of Norfloxacin

25 December, 2019
Due to its powerful bactericidal activity, norfloxacin fights microorganisms that are resistant to other drugs. What's it for? What are its side effects? Discover the answers here!

Norfloxacin is an antibiotic that belongs to the class of fluoroquinolone antibiotics. It’s a wide-spectrum bactericide against gram-positive and gram-negative aerobic pathogenic microorganisms. In this article we’ll explain the uses and side effects of norfloxacin.

This antibiotic inhibits deoxyribonucleic acid synthesis in bacteria. Therefore, due to its powerful bactericidal activity, norfloxacin fights microorganisms that are resistant to other drugs.

Uses and side effects of norfloxacin

Norfloxacin belongs to the pharmacotherapeutic group of antiseptics and urinary anti-infectives. This drug is used in the treatment of urinary tract infections, such as:

  • Cystitis: It causes acute bladder inflammation.
  • Chronic recurrent urinary tract infections
  • Cystopielitis: Inflammation of the urinary bladder and renal pelvis.

Ideally, doctors request a culture to analyze the microorganism that causes the infection’s sensitivity to treatment.

A patient with a urinary tract infection.

Norfloxacin is a drug that’s recommended in cases of urinary tract infections.

How to take norfloxacin

First of all, it’s worth mentioning that this drug should be taken without food, i.e. one or two hours after meals. However, it all depends on the culture result and the severity of the infection.

Adults with a urinary tract infection have to take 1 tablet every 12 hours for 7 to 10 days. However, if they’re suffering from acute uncomplicated cystitis, the treatment should last 3 to 7 days.

In cases of chronic recurrent infections, the treatment extends to up to 12 weeks. However, if the treatment yields good results at week four, the medical professional may reduce the dose to once a day.

Discover more here: Fight Cystitis Naturally with these 5 Teas

Adverse reactions of norfloxacin

The most common adverse reactions are gastrointestinal, psychological, and skin reactions. However, patients may suffer from nausea, headache, dizziness, heartburn, pain, and diarrhea.

Other less common side effects that can become severe, lasting, and sometimes irreversible may occur. They can affect the body at different levels and systems, thus resulting in different types of disorders and reactions.

Hypersensitivity and gastrointestinal disorder reactions

Among them:

  • Anaphylaxis
  • Angioedema
  • Dyspnea
  • Vasculitis
  • Hives
  • Arthritis
  • Myalgia and arthralgia

Moreover, among gastrointestinal disorders, pseudomembranous colitis, pancreatitis, jaundice, and hepatitis are included.

A person about to take a pill with a glass of water.

Norfloxacin can cause side effects such as upset stomach, headache, and diarrhea. However, in some cases, it leads to other more serious reactions.

Skin and subcutaneous tissue reactions

There have been cases of photosensitivity reactions in patients treated with norfloxacin who have overly exposed themselves to the sun.

If these symptoms manifest, then you should discontinue treatment with this drug. During treatment, avoid direct sun exposure to avoid potential photosensitivity risks. Other reactions may also manifest, such as:

  • Exfoliative dermatitis or erythroderma
  • Erythema multiforme
  • Vasculitis
  • Toxic epidermal necrolysis
  • And, finally, Stevens-Johnson syndrome.

You may also enjoy the following article: 6 Natural Antibiotics that You Probably Didn’t Know About

Musculoskeletal and connective tissue reactions

Tendonitis and tendon rupture, especially of the Achilles tendon, may occur. The rupture may be bilateral.

There have been cases of this disorder within the first 48 hours from the start of treatment with quinolones and fluoroquinolones. In addition, some have even occurred up to several months after the patient stopped the treatment.

The following patients may have an increased risk of tendonitis and tendon rupture:

  • Patients who have received solid organ transplants
  • Patients with renal failure
  • Older patients
  • Patients who are simultaneously treated with corticosteroids

At the first sign of tendinitis, such as pain or swelling, then you’ll need to discontinue treatment with norfloxacin and consider trying other treatments. Furthermore, you’ll have to take good care of the affected extremity to ensure proper recovery.

A woman with tendinitis.

At the first sign of tendinitis, it’s very important to stop taking norfloxacin.

Peripheral neuropathy

There have been reports of sensory or sensorimotor polyneuropathy. As a result, this condition can cause paresthesia, hypesthesia, dysesthesia, or weakness.

Patients treated with norfloxacin should inform their doctor if symptoms of neuropathy occur. These symptoms include pain, tingling, burning, numbness, and also general weakness. Thus, it’s possible to prevent the development of potentially irreversible conditions.

Heart-related reactions

Sometimes, quinolones have been associated with QT prolongation on electrocardiograms. However, they’ve also been associated with cases of arrhythmias.

Therefore, patients with hypokalemia or bradycardia should be careful. Similarly, patients who are being treated with class I or III antiarrhythmic agents should also be careful.


According to the AEMPS (Spanish Agency of Medicines and Medical Devices), medical professionals should prescribe quinolones or fluoroquinolones for the treatment of mild to moderately severe infections in exceptional cases. Namely, when other antibiotics don’t yield good results or when the patient doesn’t tolerate them.

Consult your doctor or pharmacist if you have any questions regarding treatment with this drug. In this way, you’ll avoid any possible complications.

  • Cué Brugueras, M., Morejón García, M., & Salup Díaz, R. (2005). Actualidad de las quinolonas. Revista Cubana de Farmacia.
  • Rocha, L. C. de A. (1988). Norfloxacino em infecçöes urinárias recidivantes TT  – Norfloxacin in recidivant urinary infections. Rev Bras Med.
  • Ye, Z., Wang, L., & Wen, J. (2015). A simple and sensitive method for determination of Norfloxacin in pharmaceutical preparations. Brazilian Journal of Pharmaceutical Sciences.