Adult: 400 mg bid, up to 12 wk, may be reduced to once daily if adequate suppression w/in 1st 4 wk.
Oral Complicated urinary tract infections
Adult: 400 mg bid for 10-21 days.
Oral Uncomplicated urinary tract infections
Adult: Infections caused by susceptible E. coli, Klebsiella pneumoniae, Proteus mirabilis spp: 400 mg bid for 3 days. Infections caused by other susceptible bacteria: 400 mg bid for 7-10 days.
Renal Impairment
Oral: Chronic relapsing urinary tract infections:
CrCl (mL/min)
Dosage
≤30
400 mg once daily.
Uncomplicated gonorrhoea:
CrCl (mL/min)
Dosage
≤30
400 mg as a single dose.
Complicated urinary tract infections:
CrCl (mL/min)
Dosage
≤30
400 mg once daily
Chronic bacterial prostatitis:
CrCl (mL/min)
Dosage
≤30
400 mg once daily.
Uncomplicated urinary tract infections:
CrCl (mL/min)
Dosage
≤30
400 mg once daily.
Administration
Should be taken on an empty stomach. Take 1 hr before or 2 hr after meals, w/ a glass of water. Ensure adequate hydration. Do not take w/ dairy products.
Contraindications
Hypersensitivity to norfloxacin or any other quinolone. Patients w/ known myasthenia gravis, history of tendonitis or tendon rupture associated w/ the use of quinolone.
Special Precautions
Patient w/ known prolongation of QT interval, uncorrected hypokalaemia, known or suspected CNS disorders (e.g. severe cerebral arteriosclerosis) or other factors that predispose to seizures. Kidney, heart or lung transplant recipients. Renal impairment. Pregnancy and lactation.
Adverse Reactions
Dizziness, headache, nausea, abdominal cramping, diarrhoea, vomiting, anorexia, constipation, flatulence, dyspepsia, asthenia, anal/rectal pain, peripheral neuropathy (reversible), tingling of the fingers, hyperhidrosis, arthralgia, arthritis, convulsions, muscle spasms, drug rash w/ eosinophilia and systemic symptoms syndrome (DRESS), leukocytoclastic vasculitis, tendon rupture or tendinitis, photosensitivity/phototoxicity, hepatitis, jaundice, QT interval prolongation, hypoglycaemia. Decreased Hb, WBC, hematocrit and platelet count, increased creatine kinase, urine protein and eosinophils. Potentially Fatal: Anaphylaxis, Clostridium difficile-associated diarrhoea and colitis, hepatic or acute renal failure.
This drug may cause dizziness and lightheadedness, if affected do not drive or operate machinery. Avoid unnecessary or excessive exposure to sunlight or artificial UV light (e.g. tanning beds, UVA/UVB treatment). If staying outdoors is necessary, use protective measures (e.g. sunscreen, wear loose-fitting clothes). Rest and refrain from exercise as it may increase risk of tendon rupture.
Monitoring Parameters
Periodically monitor CBC, renal and hepatic function during prolonged therapy.
Drug Interactions
Additive effect on QT interval prolongation w/ class IA (e.g. quinidine) or class III (e.g. amiodarone) antiarrhythmics and other drugs that prolong QT interval (e.g. erythromycin, TCAs, antipsychotic agents). Increased serum concentrations of theophylline. Reduced absorption w/ oral multivitamins and mineral supplements containing divalent or trivalent cations (e.g. Fe, Zn) and antacids containing Al or Mg, sucralfate, buffered didanosine. Prolonged prothrombin time w/ concomitant coumarin anticoagulant. Increased risk of severe tendon disorders w/ corticosteroids. Concurrent use w/ NSAIDs may increase the risk of CNS stimulation and convulsive seizures.
Food Interaction
Food may decrease rate and/or extent of absorption.
Action
Description: Norfloxacin is a fluoroquinolone anti-infective agent which inhibits DNA synthesis in susceptible organisms via inhibition of DNA gyrase and topoisomerase IV. Pharmacokinetics: Absorption: Rapidly but incompletely absorbed from the GI tract (approx 30-40%). Food may delay rate and/or extent of absorption. Time to peak plasma concentration: Approx 1-2 hr. Distribution: Penetrates well into tissues of genito-urinary tract; crosses the placenta and distributed into cord blood and amniotic fluid; relatively high concentrations occur in bile. Plasma protein binding: Approx 14%. Metabolism: Undergoes partial hepatic metabolism to several metabolites. Excretion: Via urine by tubular secretion and glomerular filtration w/in 24 hr (approx 30% as unchanged drug); faeces (approx 39%). Plasma half-life: 3-4 hr.
Chemical Structure
Norfloxacin Source: National Center for Biotechnology Information. PubChem Database. Norfloxacin, CID=4539, https://pubchem.ncbi.nlm.nih.gov/compound/Norfloxacin (accessed on Jan. 22, 2020)
Anon. Norfloxacin. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 24/06/2014.Buckingham R (ed). Norfloxacin. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 24/06/2014.Joint Formulary Committee. Norfloxacin. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 24/06/2014.McEvoy GK, Snow EK, Miller J et al (eds). Norfloxacin. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 24/06/2014.Noroxin Tablet, Film Coated (Merck Sharp & Dohme Corp.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 24/06/2014.Noroxin Tablets. U.S. FDA. https://www.fda.gov/. Accessed 24/06/2014.
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