Norfloxacin Side Effects
Some side effects of norfloxacin may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.
For the Consumer
Applies to norfloxacin: oral tablet
Get emergency medical help if you have any of these signs of an allergic reaction while taking norfloxacin: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Stop taking norfloxacin and call your doctor at once if you have sudden pain, snapping or popping sound, bruising, swelling, tenderness, stiffness, or loss of movement in any of your joints. Rest the joint until you receive medical care or instructions.
Call your doctor at once if you have any of these serious side effects:
diarrhea that is watery or bloody;
headache with chest pain and severe dizziness, fainting, fast or pounding heartbeats;
irregular heart rhythm, new or worsening cough, trouble breathing;
hallucinations, tremors, feeling restless or anxious, unusual thoughts or behavior, seizure (convulsions);
ringing in your ears, vision problems, pain behind your eyes;
confusion, nausea and vomiting, swelling, rapid weight gain, urinating less than usual or not at all;
numbness, burning, pain, or tingly feeling in your hands or feet;
pain in your upper stomach, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);
pale skin, easy bruising or bleeding, muscle weakness, fever, swollen glands, general ill feeling;
the first sign of any skin rash, no matter how mild; or
severe skin reaction -- fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain, followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.
Less serious side effects of norfloxacin may include:
mild nausea or diarrhea, stomach cramps, heartburn;
back pain; or
vaginal itching or discharge.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.
For Healthcare Professionals
Applies to norfloxacin: oral tablet
Norfloxacin therapy is generally well tolerated and adverse effects are mild. Adverse effects were reported in 6.5% of subjects receiving single doses and 3.6% of subjects receiving multiple doses.
The onset of pseudomembranous colitis symptoms may occur during or after antimicrobial treatment.
Quinolone class antibiotics have been associated with intestinal perforation and dysphasia.
Common (1% to 10%): Nausea (2.6% to 4.2%), abdominal cramping (1.6%)
Uncommon (0.1% to 1%): Abdominal pain (0.3% to 1%), anal/rectal pain (0.3% to 1%), constipation (0.3% to 1%), diarrhea (0.3% to 1%), dry mouth/heartburn (0.3% to 1%), dyspepsia (0.3% to 1%), flatulence (0.3% to 1%), loose stools (0.3% to 1%), vomiting (0.3% to 1%), abdominal swelling (0.1% to 0.2%), mouth ulcer (0.1% to 0.2%)
Frequency not reported: Intestinal perforation
Postmarketing reports: Dysgeusia, pseudomembranous colitis, pancreatitis, stomatitis, dysphasia
Common (1% to 10%): Headache (2% to 2.8%), dizziness (1.7% to 2.6%)
Uncommon (0.1% to 1%): Tingling of the fingers (0.3% to 1%), somnolence (0.3% to 1%)
Rare (less than 0.1%): Sensory and sensorimotor axonal polyneuropathy resulting in paresthesias, hypoesthesias, dysesthesias, weakness
Postmarketing reports: Generalized seizures, myoclonus, tremors, peripheral neuropathy, Guillain-Barre syndrome, ataxia, paresthesia, hypoesthesia, hearing loss, tinnitus
Seizures reported in association with norfloxacin therapy have occurred, generally in older patients. Norfloxacin should be used cautiously in patients who are predisposed to seizures. One patient with myasthenia gravis experienced a deterioration in her condition during two different courses of norfloxacin.
A 70-year-old male developed an itchy papulopustular eruption from the thighs to the abdomen after 3 days of therapy with norfloxacin. The patient was treated with prednisone for 15 days. A patch test one month later resulted in a reaction to quinolone mix.
A 71-year-old woman developed a fever and eosinophilia after 1 week of norfloxacin 400 mg three times a day. Laboratory results included an elevated white blood cell (WBC) count with 60.9% eosinophils as well as elevated hepatic transaminase levels, which returned to normal following the discontinuation of norfloxacin. Symptoms returned upon rechallenge 6 weeks later and resolved over several weeks after norfloxacin was replaced by ciprofloxacin.
Uncommon (0.1% to 1%): Allergies (0.1% to 0.2%)
Frequency not reported: Rash, systemic contact dermatitis, Stevens-Johnson syndrome, eosinophilic necrotizing granulomatous hepatitis, anaphylaxis, cardiovascular collapse, toxic epidermal necrolysis, erythema multiforme, exfoliative dermatitis, photosensitivity
Postmarketing reports: Anaphylactoid reactions, angioedema, dyspnea, vasculitis, urticaria, arthritis, arthralgia, myalgia
Quinolone class antibiotics have been associated with renal calculi.
Frequency not reported: Decreased renal function, nephrotic syndrome (which has occurred in patients treated with high doses), increased BUN, increased serum creatinine, renal calculi
Postmarketing reports: Interstitial nephritis, renal failure
Quinolone class antibiotics have been associated with hepatic necrosis.
Common (1% to 10%): Elevated ALT (1.4%), elevated AST (1.4% to 1.6%), elevated alkaline phosphatase (1.1%)
Frequency not reported: Elevated lactate dehydrogenase, hepatic necrosis
Postmarketing reports: Hepatitis, jaundice (including cholestatic jaundice and elevated liver function tests), hepatic failure (including fatal cases)
Common (1% to 10%): Eosinophilia (1.5%), decreased WBC (1.3% to 1.4%), decreased neutrophil count (1.4%), decreased platelet count (1%)
Uncommon (0.1% to 1%): Decreased hematocrit and hemoglobin (0.6%), increased eosinophils (0.6%)
Postmarketing reports: Leukopenia, neutropenia, hemolytic anemia, agranulocytosis, prothrombin time prolongation, thrombocytopenia
Eosinophilia was reported in 7.5% of one study population. Leukopenia and neutropenia have been reported in up to 1% of patients. Hemolytic anemia has sometimes been associated with glucose-6-phosphate dehydrogenase deficiency.
Uncommon (0.1% to 1%): Bursitis (0.1% to 0.2%)
Frequency not reported: Bilateral arthritis of the ankles, myalgia, rhabdomyolysis
Postmarketing reports: Tendonitis, tendon rupture, exacerbation of myasthenia gravis, elevated creatine kinase, muscle spasms
Quinolones, including norfloxacin, have been associated with ruptures of the shoulder, hand, Achilles, and other tendons resulting in disability or requiring surgical repair. Elderly patients and patients concomitantly using corticosteroids may be at increased risk.
Renal transplant patients have an increased risk of Achilles tendonitis and rupture over the general population. Quinolone use has been shown to increase that risk further in this population (12% in quinolone-treated patients vs. 7% in patients not treated).
Common (1% to 10%): Asthenia (0.3 to 1.3%)
Uncommon (0.1% to 1%): Fever (0.3% to 1%), back pain (0.3% to 1%), foot or hand swelling (0.1% to 0.2%), bitter taste (0.1% to 0.2%), chills (0.1% to 0.2%), edema (0.1% to 0.2%)
Uncommon (0.1% to 1%): Rash (0.3% to 1%), pruritus (0.3% to 1%), erythema (0.1% to 0.2%), urticaria (0.1% to 0.2%), pruritus ani (0.1% to 0.2%)
Frequency not reported: Erythema nodosum
Postmarketing reports: Rash, toxic epidermal necrolysis, Stevens-Johnson syndrome, erythema multiforme, exfoliative dermatitis, leukocytoclastic vasculitis, drug rash with eosinophilia and systemic symptoms (DRESS syndrome), photosensitivity/phototoxicity reactions
Quinolone class antibiotics have been associated with erythema nodosum.
Common (1% to 10%): Increased urine protein (1%)
Uncommon (0.1% to 1%): Dysmenorrhea (0.1% to 0.2%), renal colic (0.1% to 0.2%)
Frequency not reported: Glycosuria
Postmarketing reports: Crystalluria, albuminuria, candiduria, cylindruria, hematuria, vaginal candidiasis
Crystalluria has occurred in patients taking doses greater than 1200 mg/day and whose urine pH was 7.0 to 7.8.
Quinolone class antibiotics have been associated with albuminuria, candiduria, crystalluria, cylindruria, hematuria, and vaginal candidiasis.
Uncommon (0.1% to 1%): Hyperhidrosis (0.3% to 1%)
Uncommon (0.1% to 1%): Chest pain (0.1% to 0.2%), myocardial infarction (0.1% to 0.2%), palpitation (0.1% to 0.2%)
Postmarketing reports: Prolonged QTc interval, ventricular arrhythmia (including torsade de pointes), postural hypotension
Quinolone class antibiotics have been associated with postural hypotension.
Quinolone class antibiotics have been associated with nystagmus and visual disturbances.
Uncommon (0.1% to 1%): Blurred vision (0.1% to 0.2%)
Postmarketing reports: Diplopia, nystagmus, visual disturbances
Quinolone class antibiotics have been associated with acidosis, symptomatic hypoglycemia, and elevations in serum triglycerides, serum cholesterol, blood glucose, and serum potassium.
Uncommon (0.1% to 1%): Anorexia (0.1% to 1%)
Frequency not reported: Acidosis
Postmarketing reports: Symptomatic hypoglycemia, elevated serum triglycerides, elevated serum cholesterol, elevated blood glucose, elevated serum potassium
Frequency not reported: Hiccough
Quinolone class antibiotics have been associated with hiccough.
Uncommon (0.1% to 1%): Anxiety (0.1% to 0.2%), depression (0.1% to 0.2%), insomnia (0.1% to 0.2%), sleep disturbances (0.1% to 0.2%)
Frequency not reported: Manic reactions
Postmarketing reports: Psychic disturbances (including psychotic reactions and confusion)
Quinolone class antibiotics have been associated with manic reactions.
More norfloxacin resources
- norfloxacin Concise Consumer Information (Cerner Multum)
- norfloxacin MedFacts Consumer Leaflet (Wolters Kluwer)
- norfloxacin Advanced Consumer (Micromedex) - Includes Dosage Information
- Norfloxacin Professional Patient Advice (Wolters Kluwer)
- Norfloxacin Monograph (AHFS DI)
- Noroxin Prescribing Information (FDA)
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