Norfloxacin

Oral
Chronic bacterial prostatitis

Oral
Acute uncomplicated urinary tract infections, Complicated urinary tract infections

Oral
Uncomplicated gonorrhoea

Oral:
Acute uncomplicated urinary tract infections; Complicated urinary tract infections; Chronic bacterial prostatitis:

CrCl (mL/min)	Dosage
≤30	400 mg once daily.

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.

Hypersensitivity to norfloxacin or other quinolones. History of tendon disorders, tendinitis or tendon rupture. Pre-pubertal children. Pregnancy.

Patient with pre-existing or history of aortic aneurysm, and its risk factors (e.g. hypertension, peripheral atherosclerotic vascular diseases, Takayasu arteritis, giant cell arteritis, Behcet's disease, genetic disorders that involve blood vessel changes such as Marfan syndrome or Ehlers-Danlos syndrome); cardiac disease (e.g. heart failure, MI, bradycardia), congenital long QT syndrome, uncorrected electrolyte imbalance (e.g. hypokalaemia, hypomagnesaemia), history of QT prolongation; known history of myasthenia gravis, G6PD deficiency, known or suspected CNS disorder, risk factors predisposing to seizures or lowers seizure threshold, rheumatoid arthritis. Solid organ transplant recipients. Not effective and may mask symptoms of syphilis. Renal impairment. Elderly. Lactation.

Significant: Tendinitis or tendon rupture (particularly Achilles tendon), CNS effects (e.g. seizures, increased intracranial pressure including pseudotumour cerebri, toxic psychosis), peripheral neuropathy, aortic aneurysm ruptures or dissection (particularly in the elderly), QT interval prolongation; cholestatic hepatitis, hyperglycaemia, moderate to severe phototoxicity; bacterial or fungal superinfection, including Clostridium difficile-associated diarrhoea and pseudomembranous colitis (prolonged use). Rarey, haemolytic reactions (in G6PD deficient patients).
Cardiac disorders: Tachycardia, ventricular arrhythmia, torsades de pointes.
Ear and labyrinth disorders: Rarely, tinnitus.
Eye disorders: Rarely, visual disturbances.
Gastrointestinal disorders: Nausea, vomiting, abdominal pain, dyspepsia, diarrhoea.
Investigations: Increased AST, ALT, and blood alkaline phosphatase; prolonged prothrombin time, decreased haematocrit.
Musculoskeletal and connective tissue disorders: Rhabdomyolysis.
Nervous system disorders: Headache, dizziness, drowsiness.
Psychiatric disorders: Rarely, insomnia, confusion, hallucination, nervousness, disorientation, depression, anxiety, mood changes.
Renal and urinary disorders: Crystalluria (high doses).
Skin and subcutaneous tissue disorders: Rash, pruritus, petechiae. Rarely, Stevens-Johnson syndrome, exfoliative dermatitis, toxic epidermal necrolysis.
Potentially Fatal: Severe hypoglycaemia, severe exacerbation of myasthenia gravis; severe hypersensitivity reactions, including anaphylaxis.

PO: C

This drug may cause dizziness, if affected, do not drive or operate machinery. Avoid or limit exposure to excessive sunlight. Ensure adequate hydration.

Perform culture and susceptibility tests; consult local institutional recommendations before treatment initiation due to antibiotic resistance risks. Screen patients for syphilis at the time of gonorrhoeal diagnosis and 3 months later. Periodically monitor CBC, hepatic and renal function during prolonged therapy.

Increased risk of QT prolongation with agents known to prolong the QT interval (e.g. class IA and III antiarrhythmic drugs, macrolides, antipsychotics, TCAs). May increase the plasma levels of theophylline and ciclosporin. Rarely, may cause severe hypoglycaemia when given with glibenclamide. Antacids, sucralfate, multivitamins or drugs containing Fe or Zn may decrease the absorption of norfloxacin. May increase the risk of CNS stimulation and convulsive seizures with NSAIDs. May enhance the effects of anticoagulants (e.g. warfarin). May inhibit the metabolism of caffeine. Diminished urinary excretion with probenecid. Increased risk of tendinitis and tendon rupture with corticosteroids.

Food and dairy products may reduce the absorption and average peak serum concentrations of norfloxacin.

Description:
Mechanism of Action: Norfloxacin is a fluoroquinolone derivative with a broad spectrum of bactericidal activity. It exerts its antibacterial activity by inhibiting deoxyribonucleic acid (DNA) gyrase, a bacterial enzyme necessary for DNA replication, transcription, repair, recombination and transposition.
Pharmacokinetics:
Absorption: Rapidly but incompletely absorbed from the gastrointestinal tract (approx 30-40%). Food and dairy products decrease the absorption. Time to peak plasma concentration: Approx 1-2 hours.
Distribution: Penetrates well into tissues of the genitourinary tract; detected in bile, prostatic fluid and amniotic fluid. Crosses the placenta. Plasma protein binding: 10-15%.
Metabolism: Metabolised in the liver into several metabolites.
Excretion: Mainly via urine (26-32% as unchanged drug, 5-8% as metabolites); faeces (30%). Elimination half-life: 3-4 hours.

Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 4539, Norfloxacin. https://pubchem.ncbi.nlm.nih.gov/compound/4539. Accessed July 29, 2022.

Store between 15-30°C. Protect from light.

Quinolones

J01MA06 - norfloxacin ; Belongs to the class of fluoroquinolones. Used in the systemic treatment of infections.

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