See also Fluoroquinolones
Norfloxacin is a fluoroquinolone antibacterial drug with properties similar to those of ciprofloxacin, although less potent in vitro.
Norfloxacin inhibits CYP1A2 and can therefore enhance the effects of other drugs by reducing their clearance.
Comparative studies
In a double-blind, multicenter study 171 patients who had acute pyelonephritis were given intravenous cefuroxime for 2-3 days, followed by ceftibuten 200 mg bd or norfloxacin 400 mg bd for 10 days. There were fewer bacterial relapses after oral norfloxacin than ceftibuten. Adverse events were reported by 47% of the patients taking ceftibuten and by 38% of those taking norfloxacin. This difference was not significant, but diarrhea or loose stools occurred more often with ceftibuten.
Organs and Systems
Sensory systems
A corneal ulcer associated with deposits of norfloxacin in the right eye has been reported in a 40-year-old man with right trigeminal and facial nerve palsies and reduced tear secretion. He stopped using norfloxacin ophthalmic solution and recovered.
Psychological, psychiatric
There have been reports of hallucinations with norfloxacin.
Hematologic
Eosinophilia occurred in a 35-year-old man with alcoholic cirrhosis taking norfloxacin 400 mg bd for prophylaxis of spontaneous bacterial peritonitis.
Gastrointestinal
In a prospective study in women with urinary tract infections treated with pivmecillinam 400 mg bd for 3 days or norfloxacin 400 mg bd for 3 days, 36% of the pivmecillinam-treated patients and 39% of the norfloxacin-treated patients reported adverse events. Gastrointestinal symptoms were most frequent. Of the patients who took norfloxacin 4.3% had vaginal candidiasis.
Liver
Acute hepatitis has been reported with norfloxacin.
Pancreas
Norfloxacin can cause pancreatitis.
Urinary tract
Acute interstitial nephritis, probably related to norfloxacin, has been reported.
A 38-year-old woman took norfloxacin (300 mg/day) and tiaramide hydrochloride (300 mg tds) for an infection with Mycoplasma pneumoniae. One day after the start of treatment, her symptoms of cough and fever worsened and she developed lumbago and hematuria. The diagnosis was confirmed by percutaneous renal biopsy. She slowly improved without specific treatment. Lymphocyte stimulation tests were negative, but rechal-lenge with norfloxacin was followed by bilateral lumbago.
The authors identified two previous reports of acute interstitial nephritis associated with norfloxacin.
Musculoskeletal
Myalgia has been attributed to norfloxacin.
A 33-year-old man developed myalgia and rhabdomyolysis while taking norfloxacin for cystitis. He complained of general muscle fatigue, tendon disorders, and articular pain. When norfloxacin was withdrawn, his symptoms abated, with persistence of slight myalgia for 10 days.
Drug Administration
Drug formulations
The stability of norfloxacin in suspensions prepared from two brands of film-coated tablets has been studied. The vehicle consisted of tragacanth, saccharin sodium, sorbitol solution, glycerol, parabens concentrate, peppermint spirit, purified water, and syrup USP, yielding a final concentration of norfloxacin of 20 mg/ml. The resulting suspensions were chemically stable for 28 days when stored in amber glass bottles at room temperature.
Drug-Drug Interactions
Antacids
Norfloxacin can interact with antacids containing aluminium or magnesium salts, by complexation, reducing its solubility and therefore its absorption; this can result in therapeutic failure. In an in vitro study, dissolution rates were markedly reduced in the presence of all antacids studied; however, this phenomenon was practically avoided when a disintegrant (sodium starch glycolate or crospovidone) was included in the tablet.
Ciclosporin
In children undergoing renal transplantation and receiving ciclosporin, the mean daily dose of ciclosporin needed to maintain adequate trough concentrations fell when patients were treated with norfloxacin for urinary tract infections.
Oral contraceptives
Plasma concentrations of oral contraceptive steroids were unchanged by norfloxacin.
Food-Drug Interactions
The systemic availability of norfloxacin was reduced by 38-52% by dairy products.