Classifications: quinolone antibiotic; Therapeutic: antibiotic; quinolone
Pregnancy Category: C
400 mg tablets
Potent broad-spectrum antibiotic activity. Alters structure of bacterial DNA gyrase, thus promoting double-stranded DNA
breakage, thus interfering with synthesis of bacterial protein and blocking bacterial survival.
Active against many bacterial pathogens of the urinary tract.
Complicated and uncomplicated urinary tract infection (UTI) caused by susceptible organisms. Conjunctivitis.
Gonorrhea, gastroenteritis, and prevention of travelers' diarrhea.
Use in individual with known factors that predispose to seizures; history of hypersensitivity to norfloxacin and other quinolone
antibiotics; history of QT prolongation; tendon pain; pregnancy (category C), lactation; children <18 y.
Impaired kidney function, adolescents if skeletal growth is complete; G6PD deficiency; GI disease; myasthenia gravis.
Route & Dosage
|Urinary Tract Infection
Adult: PO 400 mg b.i.d.
Gonorrhea or Gonococcal Urethritis
Adult: PO 800 mg once/d
Adult: PO 400 mg q812h
- Give 1 h before or 2 h after meals with a full glass of water.
- Administer concomitant antacid at least 2 h after norfloxacin to prevent interference with absorption. Aluminum or magnesium
ions in the antacid may bind to and form insoluble complexes with the quinolone in GI tract.
- Store at 40° C (104° F) or less in tightly closed container. Do not freeze.
Adverse Effects (≥1%)Musculoskeletal:
Joint swelling, cartilage erosion in weight-bearing joints, tendonitis. In immunosuppressed adult: acute ankle and hip pain
followed by acute pain, tenderness, and swelling of tendon sheath of middle finger of both hands after 4 wk of therapy. CNS: Headache,
dizziness, lightheadedness, fatigue
, drowsiness, somnolence, depression
, seizures, peripheral neuropathy. GI: Nausea,
abdominal pain, diarrhea, vomiting, anorexia, dyspepsia, dysphagia, dry mouth, bitter taste, heartburn, flatulence, pruritus
ani, increased serum AST, ALT, alkaline phosphatase. Hematologic:
Leukopenia, neutropenia. Urogenital:
With high doses: Crystalluria (not associated with renal toxicity), vulvar irritation.
Diagnostic Test Interference
May cause false positive on opiate screening tests.
Interactions Drug: antacids
, iron, sucralfate
, zinc decrease absorption; nitrofurantoin
may antagonize antibacterial effects; may increase hypoprothrombinemic effects of warfarin;
may cause slight increase in theophylline
levels; concurrent administration with class ia
and class iii antiarrhythmics
may result in development of QT prolongation as well as torsades de points.
3040% from GI tract. Peak:
12 h. Distribution:
Renal parenchyma, gallbladder, liver, prostate; crosses placenta; distributed into breast milk. Metabolism:
In liver. Elimination:
In urine and feces. Half-Life:
Assessment & Drug Effects
- Collect urine specimens for testing before initiating antibiotic.
- Monitor patient for tendon pain. Norfloxacin should be discontinued and physician informed.
- Lab tests: Periodic WBC with differential, liver enzymes, and alkaline phosphatase, especially with prolonged use.
- Report to the physician if patient is adequately hydrated, yet I&O ratio and pattern changes are noted, or if condition
does not improve within a few days. Dosage may need to be modified.
Patient & Family Education
- Take drug at same times each day.
- Take drug exactly as prescribed. Erratic dosing can encourage emergence of resistant bacteria; underdosing or premature discontinuation
of treatment can cause return of UTI symptoms.
- Keep fluid intake high (at least 25003000 mL/d if tolerated) to provide adequate urine output and hydration, important
in the prevention of crystalluria (rare side effect).