Drug information of norfloxacin


Drug group:

Norfloxacin is an antibiotic in a group of drugs called fluoroquinolones (flor-o-KWIN-o-lones). Norfloxacin fights bacteria in the body.

Norfloxacin is used to treat different bacterial infections of the prostate or urinary tract (bladder and kidneys). Norfloxacin is also used to treat gonorrhea.

Norfloxacin may also be used for purposes not listed in this medication guide.

Mechanism of effect

The bactericidal action of Norfloxacin results from inhibition of the enzymes topoisomerase II (DNA gyrase) and topoisomerase IV, which are required for bacterial DNA replication, transcription, repair, and recombination. Norfloxacin is a broad-spectrum antibiotic agent that is shown to be effective against various Gram-positive and Gram-negative bacterial species. The fluorine atom at the 6 position increases potency against gram-negative organisms, and the piperazine moiety at the 7 position is responsible for anti-pseudomonal activity


Norfloxacin is a quinolone/fluoroquinolone antibiotic. Norfloxacin is bactericidal and its mode of action depends on blocking of bacterial DNA replication by binding itself to an enzyme called DNA gyrase, which allows the untwisting required to replicate one DNA double helix into two. Notably the drug has 100 times higher affinity for bacterial DNA gyrase than for mammalian.


10 and 15% (Serum protein binding)
absorbtion rapid
Metabolism Via liver and kidney

Norfloxacin is eliminated through metabolism, biliary excretion, and renal excretion. It is expected to undergo both glomerular filtration and tubular secretion during renal excretion, as shown by its high renal clearance rate of approximately 275 mL/min.

Drug indications

  • Cystitis
  • Urinary Tract Infection
  • Prostatitis
  • Gonococcal Infection - Uncomplicated
  • Pyelonephritis
  • Shigellosis
  • Infectious Diarrhea
  • Salmonella Enteric Fever
  • Salmonella Gastroenteritis
  • Traveler's Diarrhea
  • Traveler's Diarrhea Prophylaxis


Usual Adult Dose for Urinary Tract Infection:

Due to Escherichia coli, Klebsiella pneumoniae, or Proteus mirabilis: 400 mg orally every 12 hours for 3 days
Due to other organisms: 400 mg orally every 12 hours for 7 to 10 days

Complicated: 400 mg orally every 12 hours for 10 to 21 days

Usual Adult Dose for Cystitis:

Due to E coli, K pneumoniae, or P mirabilis: 400 mg orally every 12 hours for 3 days
Due to other organisms: 400 mg orally every 12 hours for 7 to 10 days

Usual Adult Dose for Prostatitis:

Acute or chronic: 400 mg orally every 12 hours for 28 days

Usual Adult Dose for Gonococcal Infection -- Uncomplicated:

800 mg orally one time

Due to high rates of resistance, the Centers for Disease Control and Prevention do not recommend fluoroquinolones for treatment of gonococcal infections in the United States. Ceftriaxone or oral cefixime is recommended as first-line treatment of gonorrhea in the United States. Antimicrobial susceptibility patterns should be monitored.

Doxycycline therapy for 7 days (if not pregnant) or single-dose azithromycin is also recommended for possible coexisting chlamydial infection.

The patient's sexual partner(s) should also be evaluated/treated.

Drug contraindications

You should not use this medication if you have ever had swelling or tearing of a tendon caused by taking norfloxacin or similar antibiotic

you are allergic to other fluoroquinolones (ciprofloxacin, gemifloxacin, levofloxacin, moxifloxacin, ofloxacin, and others).

Side effects

  • igns of tendon rupture--sudden pain, swelling, bruising, tenderness, stiffness, movement problems, or a snapping or popping sound in any of your joints (rest the joint until you receive medical care or instructions); or

  • nerve symptoms--numbness, tingling, burning pain, or being more sensitive to temperature, light touch, or the sense of your body position.

Stop using norfloxacin and call your doctor at once if you have:

  • headache with chest pain and severe dizziness, fainting, fast or pounding heartbeats;

  • dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);

  • muscle weakness or trouble breathing;

  • diarrhea that is watery or bloody;

  • sudden weakness or ill feeling, fever, chills, sore throat, mouth sores, easy bruising or bleeding;

  • depression, confusion, hallucinations, paranoia, tremors, feeling restless or anxious, unusual thoughts or behavior, insomnia, nightmares;

  • seizure (convulsions); or

  • increased pressure inside the skull-- severe headaches, ringing in your ears, dizziness, nausea, vision problems, pain behind your eyes

  • alfuzosin
  • amiodarone
  • antacids containing aluminum, calcium or magnesium (do not take within 2 hours of norfloxacin)
  • antipsychotics (e.g., chlorpromazine, clozapine, haloperidol, olanzapine, quetiapine, risperidone)
  • BCG
  • caffeine
  • calcium supplements and multivitamins containing calcium (do not take within 2 hours of norfloxacin)
  • cholera vaccine
  • chloroquine
  • corticosteroids (e.g., dexamethasone, hydrocortisone, prednisone)
  • cyclosporine
  • diabetes medications (e.g., chlorpropamide, glipizide, glyburide, insulin, metformin,  rosiglitazone)
  • didanosine (do not take within 2 hours of norfloxacin)
  • disopyramide
  • dofetilide
  • domperidone
  • dronedarone
  • efavirenz
  • eplerenone
  • fentanyl
  • flecainide
  • iron supplements, such as ferrous sulfate, or multivitamins containing iron (do not take within 2 hours of norfloxacin)
  • lanreotide
  • leuprolide
  • lopinavir
  • macrolide antibiotics (e.g., clarithromycin, erythromycin)
  • magnesium supplements, such as magnesium sulfate, or multivitamins containing magnesium (do not take within 2 hours of norfloxacin)
  • methadone
  • mifepristone
  • multivitamins with minerals
  • mycophenolate
  • nilotinib
  • nitrofurantoin
  • nonsteroidal anti-inflammatory medications (e.g., diclofenac, ibuprofen, ketoprofen, naproxen)
  • octreotide
  • pasireotide
  • pazopanib
  • pimozide
  • porfimer
  • primaquine
  • procainamide
  • quinapril
  • quinidine
  • quinine
  • other quinolone antibiotics (e.g., ciprofloxacin, moifloxacin, sparfloxacin)
  • saquinavir
  • selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, fluoxetine, paroxetine, sertraline)
  • serotonin antagonists (anti-emetic medications; e.g., granisetron, ondansetron)
  • sevelamer
  • sodium picosulfate
  • somatostatin
  • sotalol
  • sucralfate (do not take within 2 hours of norfloxacin)
  • sulfonamide antibiotics ('sulfas'; e.g., sulfisoxazole, sulfamethoxazole)
  • tetrabenazine
  • theophyllines (e.g., aminophylline, oxtriphylline, theophylline)
  • tizanidine
  • trazodone
  • typhoid vaccine
  • varenicline
  • voriconazole
  • warfarin
  • zinc supplements or multivitamins containing zinc (do not take within 2 hours of norfloxacin)



  • This medicine may cause severe side effects like irritated or torn tendons; nerve problems in the arms, hands, legs, or feet; and nervous system problems. These can happen alone or at the same time. They can happen within hours to weeks after starting norfloxacin. Some of these effects may not go away, and may lead to disability or death.
  • The chance of irritated or torn tendons is greater in people over the age of 60; heart, kidney, or lung transplant patients; or people taking steroid drugs. Tendon problems can happen as long as several months after treatment. Call your doctor right away if you have pain, bruising, or swelling in the back of the ankle, shoulder, hand, or other joints. Call your doctor right away if you are not able to move or bear weight on a joint or if you hear or feel a snap or pop.
  • Call your doctor right away if you have signs of nerve problems. These may include not being able to handle heat or cold; change in sense of touch; or burning, numbness, tingling, pain, or weakness in the arms, hands, legs, or feet.
  • Call your doctor right away if you have signs of nervous system problems. These may include anxiety, bad dreams, trouble sleeping, change in eyesight, dizziness, feeling confused, feeling nervous or agitated, feeling restless, hallucinations (seeing or hearing things that are not there), new or worse behavior or mood changes like depression or thoughts of suicide, seizures, or very bad headaches.
  • Do not take if you have myasthenia gravis. Very bad and sometimes deadly breathing problems have happened with norfloxacin in people who have myasthenia gravis.
  • For some health problems, norfloxacin is only for use when other drugs cannot be used or have not worked. Talk with the doctor to be sure that the benefits of norfloxacin are more than the risks.

Points of recommendation

  • If you have an allergy to norfloxacin or any other part of norfloxacin.
  • If you are allergic to norfloxacin; any part of norfloxacin; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.
  • If you have any of these health problems: Long QT on ECG, low magnesium levels, or low potassium levels.
  • If you have ever had any of these health problems: Nerve problems or tendon problems.
  • If you have had tendons get irritated or torn when taking norfloxacin or an alike drug in the past.
  • If you are not able to pass urine.
  • If you are taking probenecid.
  • If you have been taking any drugs to treat a heartbeat that is not normal.
  • If you are taking any drugs that can cause a certain type of heartbeat that is not normal (prolonged QT interval). There are many drugs that can do this. Ask your doctor or pharmacist if you are not sure.


  • If the patient is a child. This medicine is not approved for use in children.

This is not a list of all drugs or health problems that interact with norfloxacin.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take norfloxacin with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

  • Take norfloxacin at the same time of day.
  • Take on an empty stomach. Take 1 hour before or 2 hours after meals or having milk or other dairy products.
  • Take with a full glass of water.
  • Do not take dairy products, antacids, didanosine, multivitamins, minerals (calcium, iron, zinc, magnesium), or sucralfate within 2 hours of norfloxacin.
  • Keep using norfloxacin as you have been told by your doctor or other health care provider, even if you feel well.

Pregnancy level


This drug should be used during pregnancy only if the benefit outweighs the risk to the fetus; according to some authorities, use is contraindicated

Breast feeding warning

LactMed: Use is considered acceptable with monitoring of the infant for possible effects on the gastrointestinal flora (e.g., diarrhea or candidiasis [thrush, diaper rash]).
-According to some authorities, use is contraindicated.
-According to other authorities, a decision should be made to discontinue breastfeeding or discontinue the drug (at least 24 to 48 hours before restarting breastfeeding), taking into account the importance of the drug to the mother.

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