Norfloxacin: Uses, precautions & contraindications!

Norfloxacin is a quinolone antibiotic of the fluoroquinolone class, of bacteria destroying antibiotics.

It is classified as a second generation fluoroquinolone antibiotic. Some other fluoroquinolone drugs are; levofloxacin, ofloxacin, gatifloxacin, etc.


  • Skin infections
  • Joint infections
  • Bone infections
  • Lung/airway infection like Tuberculosis, pneumonia, low respiratory tract infections, bronchitis, severe sinusitis.
  • STI like gonorrhea in men & women
  • Cervicitis
  • Peritonitis
  • Bacterial inflammation & infection of the prostate
  • Typhoid fever
  • Anthrax
  • Infectious diarrhea from shigella or salmonella.
  • Intra-abdominal infections
  • Urinary tract infections (UTI)
  • Cystitis


Types of dosage forms & strengths:

  • Tablets: 200 mg, 400 mg, 800 mg
  • Norfloxacin & metronidazole suspension: 30 ml, 60 ml
  • Injection or Injection concentrate: 5%


  • For UTI: 400 mg orally every 12 hours for 10-21 days depending on severity.
  • Gonorrhea: 800 mg orally once
  • Salmonella enteric fever: 400 mg orally twice a day for 5-7 days.
  • Other doses depend on factors like the type & location of infection, bacteria, age, sex, presence of underlying diseases, immunity & doctor’s guidance.

Missed Dose: If a dose is missed & it is way past the time to take the particular dose, skip the dose & do not take it close to or along with the following dose.

In Overdose:
a) In case of overdose of norfloxacin, reversible renal toxicity can occurs.
b) Treatment of overdose includes emptying of the stomach by induced vomiting or gastric lavage.
c) Monitoring of renal function, urinary Ph & adequate hydration is recommended.


  • Nausea
  • Vomiting
  • Headache
  • Rash
  • Diarrhea
  • Runny nose
  • Anorexia
  • Abdominal pain
  • Restlessness
  • Anxiety
  • Decreased RBC & WBC count
  • Allergic reaction


  • Damage to the peripheral nerves
  • Tendinitis & tendon rupture
  • CNS effects like paranoia, delusions, insomnia, etc
  • Aggravation of symptoms of myasthenia gravis
  • Abnormal heart rhythm/beats
  • Increased bleeding
  • Dyspepsia
  • Inflammation of the vessels lining the abdomen
  • Inflammation of the urine filtering cells in the kidney
  • Increased serum alkaline phosphatase
  • Hepatitis
  • Jaundice
  • Anemia
  • Excess protein in urine
  • Respiratory failure.


This drug is contraindicated & precaution is advised in patients that have following conditions:

  • Allergic to fluoroquinolones
  • Norfloxacin can cause swelling or tearing of a tendon.
  • Rheumatoid Arthritis
  • Myasthenia gravis
  • Narrowing or hardening of arteries
  • High blood pressure
  • Genetic/hereditary disease
  • Diabetes
  • Taking diabetes medications
  • Epilepsy
  • Brain tumor
  • QT prolongation
  • Weak bones & connective tissue
  • Low levels of potassium in the body.


Drugs whose blood level is increased/or effectiveness is increased (unwanted) when given in presence of norfloxacin:

  • Theophylline given in asthma
  • Tizanidine given in muscle spasticity
  • Warfarin – blood thinning drug
  • Blood sugar reducing drugs
  • Norflox inhibits CYP1A2 enzyme system, therefore the drugs that are metabolized by this enzyme system, may lead to accumulation in the serum.

Drugs that enhance the concentration of norfloxacin when given in combination:

  • Haloperidol
  • Amphetmines can increase the cardiotoxic effect of norflox.
  • Corticosteroids can increase toxic of fluoroquinolone drugs.

Drug-Food interaction

  • Milk and other dairy products reduce the effectiveness of the drug.
  • Caffeine concentration is increased when given in addition with the drug.
  • Multivitamins can interfere with the absorption of the drug.
  • Alcohol should not be taken along with the drug.


  • Pregnancy: Norfloxacin is categorized as a category C drug, it rapidly crosses the placenta barrier & is contraindicated in pregnant women.
  • Breastfeeding: Fluoroquinolones are present in the breast milk of the mother, and therefore can pass on to infants causing serious adverse effects, therefore are not encouraged in breastfeeding mothers.
  • Children: Oral & IV drug are approved for children in two indications: Anthrax & complicated UTI.