Norfloxacin

Fluoroquinolone·Infectious Diseases - Other Antibiotics

Uncomplicated UTI, prophylaxis of Spontaneous Bacterial Peritonitis (SBP) in cirrhotic patients

Authority requiredPBSFLUOROQUINOLONENoroxin400 mg tablet+2

Max Dose

800 mg/day

Half-life

4 h

Systemic Abs.

POOR

SBP Prophylaxis

GOLD STANDARD

Rapid Summary

Overview

A narrow-application fluoroquinolone. Has very poor systemic absorption, meaning it only reaches therapeutic concentrations in the gut lumen and the urine.

Maximum Dose

Max 800 mg/day.

Clinical Focus

Never use for systemic infections (like pneumonia or bacteremia) because it does not reach the blood in high enough levels to kill anything.

Bottom Line

Norfloxacin is a urinary fluoroquinolone for uncomplicated UTIs and SBP prophylaxis, but is increasingly restricted due to resistance and carries the same fluoroquinolone class risks.

Formulation & Access

Brand Names

Noroxin

Oral Routes

Tablets (400 mg). Must be taken on an empty stomach.

Prescribing & PBS

Authority Required (PBS).

Indications & Use

Primary

PBSTGA

Uncomplicated UTI, prophylaxis of Spontaneous Bacterial Peritonitis (SBP) in cirrhotic patients.

Clinical Place

Largely reserved for SBP prophylaxis in severe liver failure, or resistant UTIs where other oral agents fail.

Quick reference

Class & Role

Fluoroquinolone — A narrow-application fluoroquinolone.

Route / Formulation

Tablets (400 mg). Must be taken on an empty stomach. (Noroxin)

Usual Dose & Max

PO 400 mg BD for 3 days. Max 800 mg/day.

Key Indication Doses

Uncomplicated UTI: PO 400 mg BD for 3 days. SBP Prophylaxis (Cirrhosis): PO 400 mg OD (Maintains a sterile gut to prevent bacterial translocation). Renal Impairment: Reduce to 400 mg OD if eGFR < 30.

Best Uses

Norfloxacin is a urinary fluoroquinolone for uncomplicated UTIs and SBP prophylaxis, but is increasingly restricted due to resistance and carries the same fluoroquinolone class risks.

Avoid / Cautions

History of tendon disorders, aortic aneurysm.

Key Risks

Musculoskeletal: Tendon rupture (Black box warning for all quinolones). Cardiovascular: Aortic dissection. MODERATE — QTc prolongation. Neurological: Neuropathy, lowered seizure threshold.

Key Interactions

Iron, Calcium, Magnesium (Antacids). Binds the drug in the gut, completely blocking absorption. Separate by 2-4 hours.

Monitoring

Warn patient to stop the drug instantly if they feel heel pain. Check eGFR.

Clinical Pearl

In patients with end-stage liver cirrhosis, gut bacteria physically migrate across the bowel wall into the ascitic fluid, causing fatal Spontaneous Bacterial Peritonitis (SBP). Because Norfloxacin absorbs poorly, it stays in the gut lumen and massacres the bacteria there, acting as a permanent shield against SBP.

Access

Authority requiredNoroxin400 mg tablet

Brand: Noroxin
PBS status: Authority required
Formulation: Tablets (400 mg)

Norfloxacin

Fluoroquinolone·Infectious Diseases - Other Antibiotics

Uncomplicated UTI, prophylaxis of Spontaneous Bacterial Peritonitis (SBP) in cirrhotic patients

Authority requiredPBSFLUOROQUINOLONENoroxin400 mg tablet+2

Max Dose

800 mg/day

Half-life

4 h

Systemic Abs.

POOR

SBP Prophylaxis

GOLD STANDARD

Rapid Summary

Overview

A narrow-application fluoroquinolone. Has very poor systemic absorption, meaning it only reaches therapeutic concentrations in the gut lumen and the urine.

Maximum Dose

Max 800 mg/day.

Clinical Focus

Never use for systemic infections (like pneumonia or bacteremia) because it does not reach the blood in high enough levels to kill anything.

Bottom Line

Norfloxacin is a urinary fluoroquinolone for uncomplicated UTIs and SBP prophylaxis, but is increasingly restricted due to resistance and carries the same fluoroquinolone class risks.

Formulation & Access

Brand Names

Noroxin

Oral Routes

Tablets (400 mg). Must be taken on an empty stomach.

Prescribing & PBS

Authority Required (PBS).

Indications & Use

Primary

PBSTGA

Uncomplicated UTI, prophylaxis of Spontaneous Bacterial Peritonitis (SBP) in cirrhotic patients.

Clinical Place

Largely reserved for SBP prophylaxis in severe liver failure, or resistant UTIs where other oral agents fail.

Quick reference

Class & Role

Fluoroquinolone — A narrow-application fluoroquinolone.

Route / Formulation

Tablets (400 mg). Must be taken on an empty stomach. (Noroxin)

Usual Dose & Max

PO 400 mg BD for 3 days. Max 800 mg/day.

Key Indication Doses

Uncomplicated UTI: PO 400 mg BD for 3 days. SBP Prophylaxis (Cirrhosis): PO 400 mg OD (Maintains a sterile gut to prevent bacterial translocation). Renal Impairment: Reduce to 400 mg OD if eGFR < 30.

Best Uses

Norfloxacin is a urinary fluoroquinolone for uncomplicated UTIs and SBP prophylaxis, but is increasingly restricted due to resistance and carries the same fluoroquinolone class risks.

Avoid / Cautions

History of tendon disorders, aortic aneurysm.

Key Risks

Musculoskeletal: Tendon rupture (Black box warning for all quinolones). Cardiovascular: Aortic dissection. MODERATE — QTc prolongation. Neurological: Neuropathy, lowered seizure threshold.

Key Interactions

Iron, Calcium, Magnesium (Antacids). Binds the drug in the gut, completely blocking absorption. Separate by 2-4 hours.

Monitoring

Warn patient to stop the drug instantly if they feel heel pain. Check eGFR.

Clinical Pearl

Access

Authority requiredNoroxin400 mg tablet

Brand: Noroxin
PBS status: Authority required
Formulation: Tablets (400 mg)