Norfloxacin

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one and do not take more than 2 doses of norfloxacin in one day.

CHIBROXIN (norfloxacin) Ophthalmic Solution is a clear, colorless to light yellow solution.

No. 3526 CHIBROXIN (norfloxacin) Ophthalmic Solution 0.3% is supplied in a white, opaque, plastic OCUMETER* ophthalmic dispenser with a controlled drop tip as follows:

NDC 0006-3526-03, 5 mL.

Storage

Store CHIBROXIN (norfloxacin) Ophthalmic Solution at room temperature, 15°-30°C (59°-86°F). Protect from light.

*Registered trademark of MERCK & CO., INC.

In fasting healthy volunteers, at least 30-40% of an oral dose of NOROXIN is absorbed. Absorption is rapid following single doses of 200 mg, 400 mg and 800 mg. At the respective doses, mean peak serum and plasma concentrations of 0.8, 1.5 and 2.4 μg/mL are attained approximately one hour after dosing. The presence of food and/or dairy products may decrease absorption. The effective half-life of norfloxacin in serum and plasma is 3-4 hours. Steady-state concentrations of norfloxacin will be attained within two days of dosing.

In healthy elderly volunteers (65-75 years of age with normal renal function for their age), norfloxacin is eliminated more slowly because of their slightly decreased renal function. Following a single 400-mg dose of norfloxacin, the mean (± SD) AUC and Cmax of 9.8 (2.83) μg•hr/mL and 2.02 (0.77) μg/mL, respectively, were observed in healthy elderly volunteers. The extent of systemic exposure was slightly higher than that seen in younger adults (AUC 6.4 μg•hr/mL and Cmax 1.5 μg/mL). Drug absorption appears unaffected. However, the effective half-life of norfloxacin in these elderly subjects is 4 hours.

There is no information on accumulation of norfloxacin with repeated administration in elderly patients. However, no dosage adjustment is required based on age alone. In elderly patients with reduced renal function, the dosage should be adjusted as for other patients with renal impairment (see DOSAGE AND ADMINISTRATION, Renal Impairment).

The disposition of norfloxacin in patients with creatinine clearance rates greater than 30 mL/min/1.73 m² is similar to that in healthy volunteers. In patients with creatinine clearance rates equal to or less than 30 mL/min/1.73 m², the renal elimination of norfloxacin decreases so that the effective serum half-life is 6.5 hours. In these patients, alteration of dosage is necessary (see DOSAGE AND ADMINISTRATION). Drug absorption appears unaffected by decreasing renal function.

Norfloxacin is eliminated through metabolism, biliary excretion, and renal excretion. After a single 400-mg dose of NOROXIN, mean antimicrobial activities equivalent to 278, 773, and 82 μg of norfloxacin/g of feces were obtained at 12, 24, and 48 hours, respectively. Renal excretion occurs by both glomerular filtration and tubular secretion as evidenced by the high rate of renal clearance (approximately 275 mL/min). Within 24 hours of drug administration, 26 to 32% of the administered dose is recovered in the urine as norfloxacin with an additional 5-8% being recovered in the urine as six active metabolites of lesser antimicrobial potency. Only a small percentage (less than 1%) of the dose is recovered thereafter. Fecal recovery accounts for another 30% of the administered dose. In elderly subjects (average creatinine clearance 91 mL/min/1.73 m²) approximately 22% of the administered dose was recovered in urine and renal clearance averaged 154 mL/min.

Two to three hours after a single 400-mg dose, urinary concentrations of 200 μg/mL or more are attained in the urine. In healthy volunteers, mean urinary concentrations of norfloxacin remain above 30 μg/mL for at least 12 hours following a 400-mg dose. The urinary pH may affect the solubility of norfloxacin. Norfloxacin is least soluble at urinary pH of 7.5 with greater solubility occurring at pHs above and below this value. The serum protein binding of norfloxacin is between 10 and 15%.

The following are mean concentrations of norfloxacin in various fluids and tissues measured 1 to 4 hours post-dose after two 400-mg doses, unless otherwise indicated:

Renal Parenchyma 7.3 μg/g
Prostate 2.5 μg/g
Seminal Fluid 2.7 μg/mL
Testicle 1.6 μg/g
Uterus/Cervix 3.0 μg/g
Vagina 4.3 μg/g
Fallopian Tube 1.9 μg/g
Bile 6.9 μg/mL (after two 200-mg doses)

Microbiology

Norfloxacin inhibits bacterial deoxyribonucleic acid synthesis and is bactericidal. At the molecular level, three specific events are attributed to norfloxacin in E. coli cells:

1. inhibition of the ATP-dependent DNA supercoiling reaction catalyzed by DNA gyrase,
2. inhibition of the relaxation of supercoiled DNA,
3. promotion of double-stranded DNA breakage.

The fluorine atom at the 6 position provides increased potency against gram-negative organisms, and the piperazine moiety at the 7 position is responsible for antipseudomonal activity.

Resistance to norfloxacin due to spontaneous mutation in vitro is a rare occurrence (range: 10-9 to 10-12 cells). Resistant organisms have emerged during therapy with norfloxacin in less than 1% of patients treated. Organisms in which development of resistance is greatest are the following:

Pseudomonas aeruginosa
Klebsiella pneumoniae
Acinetobacter spp.
Enterococcus spp.

For this reason, when there is a lack of satisfactory clinical response, repeat culture and susceptibility testing should be done. Nalidixic acid-resistant organisms are generally susceptible to norfloxacin in vitro; however, these organisms may have higher minimum inhibitory concentrations (MICs) to norfloxacin than nalidixic acid-susceptible strains. There is generally no cross-resistance between norfloxacin and other classes of antibacterial agents. Therefore, norfloxacin may demonstrate activity against indicated organisms resistant to some other antimicrobial agents including the aminoglycosides, penicillins, cephalosporins, tetracyclines, macrolides, and sulfonamides, including combinations of sulfamethoxazole and trimethoprim. Antagonism has been demonstrated in vitro between norfloxacin and nitrofurantoin.

Norfloxacin has in vitro activity against a broad range of gram-positive and gram-negative aerobic bacteria.

Norfloxacin has been shown to be active against most strains of the following microorganisms both in vitro and in clinical infections as described in the INDICATIONS AND USAGE section.

Enterococcus faecalis
Staphylococcus aureus
Staphylococcus epidermidis
Staphylococcus saprophyticus
Streptococcus agalactiae

Citrobacter freundii
Enterobacter aerogenes
Enterobacter cloacae
Escherichia coli
Klebsiella pneumoniae
Neisseria gonorrhoeae
Proteus mirabilis
Proteus vulgaris
Pseudomonas aeruginosa
Serratia marcescens

The following in vitro data are available, but their clinical significance is unknown.

Norfloxacin exhibits in vitro MICs of ≤ 4 μg/mL against most ( ≥ 90%) strains of the following microorganisms; however, the safety and effectiveness of norfloxacin in treating clinical infections due to these microorganisms have not been established in adequate and well-controlled clinical trials.

Citrobacter diversus
Edwardsiella tarda
Enterobacter agglomerans
Haemophilus ducreyi
Klebsiella oxytoca
Morganella morganii
Providencia alcalifaciens
Providencia rettgeri
Providencia stuartii
Pseudomonas fluorescens
Pseudomonas stutzeri

Ureaplasma urealyticum

NOROXIN is not generally active against obligate anaerobes.

Norfloxacin has not been shown to be active against Treponema pallidum (see WARNINGS).

Susceptibility Tests

Quantitative methods are used to determine antimicrobial MICs. These MICs provide estimates of the susceptibility of bacteria to antimicrobial compounds. The MICs should be determined using a standardized procedure. Standardized procedures are based on a dilution method{1} (broth, agar, or microdilution) or equivalent with standardized inoculum concentrations and standardized concentrations of norfloxacin powder. The MIC values should be interpreted according to the criteria outlined in Table 1.

Quantitative methods that require measurement of zone diameters also provide reproducible estimates of the susceptibility of bacteria to antimicrobial compounds. One such standardized procedure{2} requires the use of standardized inoculum concentrations. This procedure uses paper disks impregnated with 10-μg norfloxacin to test the susceptibility of microorganisms to norfloxacin. Reports from the laboratory providing results of the standard single-disk susceptibility test with a 10-μg norfloxacin disk should be interpreted according to the criteria outlined in Table 1. Interpretation involves correlation of the diameter obtained in the disk test with the MIC for norfloxacin.

Table 1: Susceptibility Interpretive Criteria for Norfloxacin

A report of “Susceptible” indicates that the pathogen is likely to be inhibited if the antimicrobial compound in the blood reaches the concentrations usually achievable. A report of “Intermediate” indicates that the result should be considered equivocal, and, if the microorganism is not fully susceptible to alternative, clinically feasible drugs, the test should be repeated. This category implies possible clinical applicability in body sites where the drug is physiologically concentrated or in situations where high dosage of drug can be used. This category also provides a buffer zone which prevents small uncontrolled technical factors from causing major discrepancies in interpretation. A report of “Resistant” indicates that the pathogen is not likely to be inhibited if the antimicrobial compound in the blood reaches the concentrations usually achievable; other therapy should be selected.

Standardized susceptibility test procedures require the use of laboratory control microorganisms to control the technical aspects of the laboratory procedures. Standard norfloxacin powder should provide the MIC values outlined in Table 2. For the diffusion techniques, the 10-μg norfloxacin disk should provide the zone diameters outlined in Table 2.

Table 2: Quality Control for Susceptibility Testing

Animal Pharmacology

Norfloxacin and related drugs have been shown to cause arthropathy in immature animals of most species tested (see WARNINGS).

Crystalluria has occurred in laboratory animals tested with norfloxacin. In dogs, needle-shaped drug crystals were seen in the urine at doses of 50 mg/kg/day. In rats, crystals were reported following doses of 200 mg/kg/day.

Embryo lethality and slight maternotoxicity (vomiting and anorexia) were observed in cynomolgus monkeys at doses of 150 mg/kg/day or higher.

Ocular toxicity, seen with some related drugs, was not observed in any norfloxacin-treated animals.

REFERENCES

1 Clinical and Laboratory Standards Institute, Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically -Eighth edition, Approved Standard CLSI Document M7-A8, Vol. 29, No. 2, CLSI, Wayne, PA, 2009.

2. Clinical and Laboratory Standards Institute, Performance standards for antimicrobial disk susceptibility tests -Tenth edition, Approved Standard CLSI Document M2-A10, Vol. 29, No. 1, CLSI, Wayne, PA, 2009.

Your pharmacist has additional information about norfloxacin ophthalmic written for health professionals that you may read.

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

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Norfloxacin may be found in some form under the following brand names:

• Chibroxin

• Noroxin

The dose your doctor recommends will depend on the infection being treated as well as your kidney function and your age. 

The recommended dose for urinary tract infections is 400 mg every 12 hours (twice daily) for 3 to 21 days.

The recommended dose for sexually transmitted diseases (gonorrhea) is a single dose of 800 mg.

For prostatitis, the recommended dose is 400 mg every 12 hours for 28 days.

• Usually bactericidal.1 2 11 17 18 20 47 59 106 145

• Like other fluoroquinolones, norfloxacin inhibits bacterial DNA gyrase and topoisomerase IV.2 13 15 20 70 145 205 206 207 214

• Spectrum of activity includes many gram-positive aerobic bacteria, many gram-negative aerobic bacteria, a few gram-positive anaerobic bacteria, and some other organisms (e.g., Chlamydia, Mycoplasma, Mycobacterium).1 17 18 19 20 29 30 33 34 41 45 66 71 78 80 102 159 178 185 189 205 207 209 Not usually active against obligate anaerobes.1 2 17 18 19 20 46 54 56 71 176 187 189 205 Inactive against fungi and viruses.17 153

• Gram-positive aerobic cocci: Active in vitro and in clinical infections against S. aureus,1 2 33 34 39 41 45 46 48 51 56 57 58 60 62 80 81 82 84 88 90 94 97 100 159 162 163 165 171 176 178 183 184 S. epidermidis,1 2 33 34 41 45 48 56 60 80 82 88 90 159 162 165 171 178 S. saprophyticus,1 2 80 166 170 177 184 S. agalactiae (group B streptococci),1 33 41 46 48 57 58 60 81 82 100 163 165 176 189 and Enterococcus faecalis.1 2 18 33 34 41 45 46 48 56 57 58 60 62 80 81 84 88 89 96 100 159 163 165 171 176 178 288 Although some strains of Streptococcus pneumoniae,33 34 39 41 46 57 58 60 81 82 100 159 176 189 S. pyogenes (group A β-hemolytic streptococci),33 34 41 46 48 56 58 60 81 82 100 159 162 163 165 171 176 189 groups C and G streptococci,33 34 60 165 176 189 viridans streptococci,20 33 41 82 and nonenterococcal group D streptococci33 39 are inhibited in vitro by norfloxacin, many strains of these gram-positive bacteria are relatively resistant to the drug.17 18 20 28 33 41 60 82 189

• Gram-positive aerobic bacilli: Active in vitro against Bacillus cereus,2 Corynebacterium,23 33 74 and Listeria monocytogenes.33 34 41 60 165 177 179 Nocardia asteroides usually are resistant.44

• Gram-negative aerobes: Active in vitro and in clinical infections against Ps. aeruginosa1 2 17 33 34 37 39 41 45 46 48 56 57 58 60 62 80 81 82 84 88 90 92 96 100 159 162 165 178 184 189 205 and most Enterobacteriaceae (including C. freundii, E. aerogenes, E. cloacae, E. coli, K. pneumoniae, P. mirabilis, P. vulgaris, S. marcescens).1 17 18 19 20 29 33 34 36 37 38 39 40 41 48 55 56 57 58 60 80 81 82 159 166 176 189 205 207 Also active in vitro against Acinetobacter,2 33 34 41 45 46 48 56 60 62 84 88 96 165 189 205 Aeromonas,31 33 34 40 41 53 165 173 C. diversus,1 Edwardsiella tarda,1 E. agglomerans,1 Haemophilus ducreyi,1 H. influenzae,33 34 39 45 46 48 58 81 82 84 100 159 162 165 171 184 189 K. oxytoca,1 Moraxella catarrhalis,33 34 45 46 179 187 189 204 Morganella morganii,1 Providencia (including P. alcalifaciens, P. rettgeri, P. stuartii),1 other Pseudomonas (e.g., Ps. acidovorans, Ps. fluorescens, Ps. putida, Ps. stutzeri),1 46 62 96 and Vibrio.2 17 25 167 173

• Other organisms: Has some in vitro activity against Chlamydia trachomatis,30 52 66 78 185 215 Mycoplasma hominis,64 159 M. pneumoniae,158 Ureaplasma urealyticum,52 64 M. tuberculosis,28 32 222 and some other mycobacteria.28 32 222

• N. gonorrhoeae with decreased susceptibility to norfloxacin and other fluoroquinolones (quinolone-resistant N. gonorrhoeae; QRNG) are widely disseminated worldwide, including in the US.319 320 322 323 324 325 326 327 328 336 358

• Some cross-resistance occurs between norfloxacin and other fluoroquinolones.17 56 71 145 237 320 323 326

• Store at room temperature.
• Store in a dry place. Do not store in a bathroom.
• Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
• Check with your pharmacist about how to throw out unused drugs.

(nor FLOKS a sin)

Uncomplicated and complicated urinary tract infections caused by susceptible gram-negative and gram-positive bacteria; sexually transmitted disease (eg, uncomplicated urethral and cervical gonorrhea) caused by N. gonorrhoeae; prostatitis due to E. coli

Note: As of April 2007, the CDC no longer recommends the use of fluoroquinolones for the treatment of gonococcal disease.

Limitations of use: Because fluoroquinolones have been associated with disabling and potentially irreversible serious adverse reactions (eg, tendinitis and tendon rupture, peripheral neuropathy, CNS effects), reserve norfloxacin for use in patients who have no alternative treatment options for acute uncomplicated urinary tract infections.

Store at 25°C (77°F); excursions permitted to 15°C to 30°C (59°F to 86°F). Keep container tightly closed.

Aminolevulinic Acid (Systemic): Photosensitizing Agents may enhance the photosensitizing effect of Aminolevulinic Acid (Systemic). Avoid combination

Aminolevulinic Acid (Topical): Photosensitizing Agents may enhance the photosensitizing effect of Aminolevulinic Acid (Topical). Monitor therapy

Antacids: May decrease the absorption of Quinolone Antibiotics. Of concern only with oral administration of quinolones. Exceptions: Sodium Bicarbonate. Consider therapy modification

BCG (Intravesical): Antibiotics may diminish the therapeutic effect of BCG (Intravesical). Avoid combination

BCG Vaccine (Immunization): Antibiotics may diminish the therapeutic effect of BCG Vaccine (Immunization). Monitor therapy

Blood Glucose Lowering Agents: Quinolone Antibiotics may enhance the hypoglycemic effect of Blood Glucose Lowering Agents. Quinolone Antibiotics may diminish the therapeutic effect of Blood Glucose Lowering Agents. Specifically, if an agent is being used to treat diabetes, loss of blood sugar control may occur with quinolone use. Monitor therapy

Caffeine and Caffeine Containing Products: Norfloxacin may increase the serum concentration of Caffeine and Caffeine Containing Products. Monitor therapy

Calcium Salts: May decrease the absorption of Quinolone Antibiotics. Of concern only with oral administration of both agents. Exceptions: Calcium Chloride. Consider therapy modification

Cholera Vaccine: Antibiotics may diminish the therapeutic effect of Cholera Vaccine. Avoid combination

Corticosteroids (Systemic): May enhance the adverse/toxic effect of Quinolone Antibiotics. Specifically, the risk of tendonitis and tendon rupture may be increased. Monitor therapy

CycloSPORINE (Systemic): Norfloxacin may decrease the metabolism of CycloSPORINE (Systemic). Monitor therapy

Delamanid: Quinolone Antibiotics may enhance the QTc-prolonging effect of Delamanid. Management: Avoid concomitant use of delamanid and quinolone antibiotics if possible. If coadministration is considered to be unavoidable, frequent monitoring of electrocardiograms (ECGs) throughout the full delamanid treatment period should occur. Consider therapy modification

Didanosine: Quinolone Antibiotics may decrease the serum concentration of Didanosine. Didanosine may decrease the serum concentration of Quinolone Antibiotics. Management: Administer oral quinolones at least 2 hours before or 6 hours after didanosine. Monitor for decreased therapeutic effects of quinolones, particularly if doses cannot be separated as recommended. This does not apply to unbuffered enteric coated didanosine. Consider therapy modification

Heroin: Quinolone Antibiotics may enhance the adverse/toxic effect of Heroin. Monitor therapy

Highest Risk QTc-Prolonging Agents: QTc-Prolonging Agents (Indeterminate Risk and Risk Modifying) may enhance the QTc-prolonging effect of Highest Risk QTc-Prolonging Agents. Management: Avoid such combinations when possible. Use should be accompanied by close monitoring for evidence of QT prolongation or other alterations of cardiac rhythm. Consider therapy modification

Iron Salts: May decrease the serum concentration of Quinolone Antibiotics. Management: Administer oral quinolones at least several hours before (4 h for moxi- and sparfloxacin, 2 h for others) or after (8 h for moxi-, 6 h for cipro/dela-, 4 h for lome-, 3 h for gemi-, and 2 h for levo-, nor-, or ofloxacin or nalidixic acid) oral iron salts. Exceptions: Ferric Carboxymaltose; Ferric Gluconate; Ferric Hydroxide Polymaltose Complex; Ferric Pyrophosphate Citrate; Ferumoxytol; Iron Dextran Complex; Iron Sucrose. Consider therapy modification

Lactobacillus and Estriol: Antibiotics may diminish the therapeutic effect of Lactobacillus and Estriol. Monitor therapy

Lanthanum: May decrease the serum concentration of Quinolone Antibiotics. Management: Administer oral quinolone antibiotics at least one hour before or four hours after lanthanum. Consider therapy modification

Magnesium Salts: May decrease the serum concentration of Quinolone Antibiotics. Management: Administer oral quinolones several hours before (4 h for moxi- and sparfloxacin, 2 h for others) or after (8 h for moxi-, 6 h for cipro/dela-, 4 h for lome-, 3 h for gemi-, and 2 h for levo-, nor-, or ofloxacin or nalidixic acid) oral magnesium salts. Consider therapy modification

MiFEPRIStone: May enhance the QTc-prolonging effect of QTc-Prolonging Agents (Indeterminate Risk and Risk Modifying). Management: Though the drugs listed here have uncertain QT-prolonging effects, they all have some possible association with QT prolongation and should generally be avoided when possible. Consider therapy modification

Moderate Risk QTc-Prolonging Agents: QTc-Prolonging Agents (Indeterminate Risk and Risk Modifying) may enhance the QTc-prolonging effect of Moderate Risk QTc-Prolonging Agents. Monitor therapy

Multivitamins/Minerals (with ADEK, Folate, Iron): May decrease the serum concentration of Quinolone Antibiotics. Specifically, polyvalent cations in multivitamin products may decrease the absorption of orally administered quinolone antibiotics. Management: Interactions can be minimized by administering the oral quinolone at least 2 hours before, or 6 hours after, the dose of a multivitamin that contains polyvalent cations (i.e., calcium, iron, magnesium, selenium, zinc). Consider therapy modification

Multivitamins/Minerals (with AE, No Iron): May decrease the serum concentration of Quinolone Antibiotics. Specifically, minerals in the multivitamin/mineral product may impair absorption of quinolone antibiotics. Management: Interactions can be minimized by administering the oral quinolone at least 2 hours before, or 6 hours after, the dose of a multivitamin that contains polyvalent cations (i.e., calcium, iron, magnesium, selenium, zinc). Consider therapy modification

Mycophenolate: Quinolone Antibiotics may decrease the serum concentration of Mycophenolate. Specifically, quinolones may decrease concentrations of the active metabolite of mycophenolate. Monitor therapy

Nadifloxacin: May enhance the adverse/toxic effect of Quinolone Antibiotics. Avoid combination

Nitrofurantoin: May diminish the therapeutic effect of Norfloxacin. Avoid combination

Nonsteroidal Anti-Inflammatory Agents: May enhance the neuroexcitatory and/or seizure-potentiating effect of Quinolone Antibiotics. Nonsteroidal Anti-Inflammatory Agents may increase the serum concentration of Quinolone Antibiotics. Monitor therapy

Porfimer: Photosensitizing Agents may enhance the photosensitizing effect of Porfimer. Monitor therapy

Probenecid: May decrease the excretion of Quinolone Antibiotics. Specifically, probenecid may decreased the renal excretion of quinolone antibiotics. Probenecid may increase the serum concentration of Quinolone Antibiotics. Monitor therapy

Quinapril: May decrease the serum concentration of Quinolone Antibiotics. Management: Separate doses of quinapril and oral quinolones by at least 2 hours in order to reduce the risk of interaction. Monitor for reduced efficacy of the quinolone if these products are used concomitantly. Consider therapy modification

Sevelamer: May decrease the absorption of Quinolone Antibiotics. Management: Administer oral quinolones at least 2 hours before or 6 hours after sevelamer. Consider therapy modification

Sodium Picosulfate: Antibiotics may diminish the therapeutic effect of Sodium Picosulfate. Management: Consider using an alternative product for bowel cleansing prior to a colonoscopy in patients who have recently used or are concurrently using an antibiotic. Consider therapy modification

Strontium Ranelate: May decrease the serum concentration of Quinolone Antibiotics. Management: In order to minimize any potential impact of strontium ranelate on quinolone antibiotic concentrations, it is recommended that strontium ranelate treatment be interrupted during quinolone therapy. Avoid combination

Sucralfate: May decrease the serum concentration of Quinolone Antibiotics. Management: Administer oral quinolones at least 2 hours before or 6 hours after the sucralfate dose. Greater separation of doses may further lessen the risk for a significant interaction. Consider therapy modification

Theophylline Derivatives: Quinolone Antibiotics may decrease the metabolism of Theophylline Derivatives. Ciprofloxacin and enoxacin are of greatest concern. Theophylline/quinolone therapy might augment the seizure-producing potential of each of the individual agents. Exceptions: Dyphylline. Consider therapy modification

Typhoid Vaccine: Antibiotics may diminish the therapeutic effect of Typhoid Vaccine. Only the live attenuated Ty21a strain is affected. Management: Vaccination with live attenuated typhoid vaccine (Ty21a) should be avoided in patients being treated with systemic antibacterial agents. Use of this vaccine should be postponed until at least 3 days after cessation of antibacterial agents. Consider therapy modification

Varenicline: Quinolone Antibiotics may increase the serum concentration of Varenicline. Management: Monitor for increased varenicline adverse effects with concurrent use of levofloxacin or other quinolone antibiotics, particularly in patients with severe renal impairment. International product labeling recommendations vary. Consult appropriate labeling. Monitor therapy

Verteporfin: Photosensitizing Agents may enhance the photosensitizing effect of Verteporfin. Monitor therapy

Vitamin K Antagonists (eg, warfarin): Quinolone Antibiotics may enhance the anticoagulant effect of Vitamin K Antagonists. Monitor therapy

Zinc Salts: May decrease the serum concentration of Quinolone Antibiotics. Management: Administer oral quinolones at least several hours before (4 h for moxi- and sparfloxacin, 2 h for others) or after (8 h for moxi-, 6 h for cipro/dela-, 4 h for lome-, 3 h for gemi-, and 2 h for levo-, nor-, or ofloxacin or nalidixic acid) oral zinc salts. Exceptions: Zinc Chloride. Consider therapy modification

Applies to norfloxacin: oral tablet

Along with its needed effects, norfloxacin may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking norfloxacin:

• Chest pain or discomfort
• chills
• diarrhea
• discouragement
• fast, irregular, pounding, or racing heartbeat or pulse
• feeling sad or empty
• fever
• flushing or redness of the skin
• hives or welts, itching, or skin rash
• increased sweating
• irritability
• irritation or soreness of the mouth
• itching of the rectal area
• lack of appetite
• loss of interest or pleasure
• nausea
• pain and inflammation at the joints
• pain or discomfort in the arms, jaw, back, or neck
• redness of the skin
• shortness of breath
• sweating
• swelling of the foot or hand
• swelling of the stomach
• tingling of the fingers
• tiredness
• trouble with concentrating
• trouble with sleeping
• unusually warm skin
• vomiting

• Abdominal or stomach cramps or tenderness
• anxiety
• back, leg, or stomach pains
• black, tarry stools
• bleeding gums
• blistering, peeling, or loosening of the skin
• bloating
• blood in the urine or stools
• blurred vision
• bone pain
• burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
• clay-colored stools
• cold sweats
• constipation
• cool, pale skin
• cough or hoarseness
• cracks in the skin
• dark-colored urine
• decreased frequency or amount of urine
• diarrhea, watery and severe, which may also be bloody
• difficulty with breathing, chewing, swallowing, or talking
• difficulty with moving
• dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
• double vision
• drooping eyelids
• dry mouth
• dry skin
• false sense of well-being
• fever with or without chills
• fruit-like breath odor
• general body swelling
• general feeling of tiredness or weakness
• greatly decreased frequency of urination or amount of urine
• headache
• inability to move the arms and legs
• increased blood pressure
• increased hunger
• increased sensitivity of the skin to sunlight
• increased thirst
• increased urination
• indigestion
• irregular or slow heart rate
• large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
• light-colored stools
• loss of heat from the body
• lower back or side pain
• mood or mental changes
• mood swings
• muscle aching or cramping
• muscle pain or stiffness
• muscle weakness
• nightmares
• nosebleeds
• numbness or tingling in the hands, feet, or lips
• pain or burning while urinating
• pain, inflammation, or swelling in the calves, shoulders, or hands
• pain, swelling, or redness in the joints
• painful or difficult urination
• pains in the stomach, side, or abdomen, possibly radiating to the back
• personality changes
• pinpoint red spots on the skin
• puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
• red skin lesions, often with a purple center
• red, irritated eyes
• red, swollen skin
• scaly skin
• seeing, hearing, or feeling things that are not there
• seizures
• severe sunburn
• severe tiredness
• shakiness and unsteady walk
• slurred speech
• sore throat
• sores, ulcers, or white spots on the lips or in the mouth
• sores, welting, or blisters
• stomach pain, continuing
• sudden decrease in the amount of urine
• sudden numbness and weakness in the arms and legs
• swelling of the face, fingers, or lower legs
• swelling or inflammation of the mouth
• swollen glands
• tightness in the chest
• unexplained weight loss
• unpleasant breath odor
• unsteadiness, awkwardness, trembling, or other problems with muscle control or coordination
• unusual behavior, such as disorientation to time or place, failure to recognize people, hyperactivity, or restlessness
• unusual bleeding or bruising
• unusual tiredness or weakness
• unusual weight loss
• vomiting of blood
• weakness in the arms, hands, legs, or feet
• weight gain
• yellowing of the eyes or skin

Some side effects of norfloxacin may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

• Lack or loss of strength

• Acid or sour stomach
• belching
• bitter taste
• cramps
• excess air or gas in the stomach or intestines
• full feeling
• heartburn
• heavy bleeding
• pain
• passing gas
• sleepiness or unusual drowsiness
• stomach discomfort, upset, or pain
• weight loss

• Change in taste
• continuing ringing or buzzing or other unexplained noise in the ears
• hearing loss
• itching of the vagina or outside genitals
• loss of taste
• pain during sexual intercourse
• seeing double
• thick, white curd-like vaginal discharge without odor or with mild odor
• uncontrolled eye movements

Substance Name

Norfloxacin

CAS Registry Number

70458-96-7

Drug Class

Antiinfective Agents

Antibacterial Agents

Quinolones

Fluoroquinolones