Is norfloxacin good for stomach infection?

Posted on  December 1, 2020, Edited by Jason, Category  

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What is norfloxacin?

1. Definition

Norfloxacin is the third-generation quinolone antibacterial drugs that can hinder the action of DNA gyrase of pathogenic bacteria in the digestive tract and have an inhibitory effect on bacteria. It is a commonly used drug for the treatment of enteritis and dysentery. However, this medicine has a delaying effect on the bone formation of minors and will affect their development, so minors are not allowed to take it. It is suitable for respiratory and urinary tract infections, gonorrhea and prostatitis caused by sensitive bacteria.

2. Traits

This product is off-white to light yellow crystalline powder; odorless, slightly bitter; hygroscopic. Norfloxacin is slightly soluble in dimethylformamide and very slightly soluble in water or ethanol; easily soluble in acetic acid, hydrochloric acid or sodium hydroxide solution. The melting point of norfloxacin is 218~224 ℃.

3. Pharmacology and Toxicology

Norflxoacin is a fluoroquinolone antibacterial drug with a broad-spectrum antibacterial effect, and especially it has high antibacterial activity against aerobic gram-negative bacilli, and good antibacterial effect in vitro against the following bacteria: most bacteria of Enterobacteriaceae, including citric acid Enterobacter species such as Bacillus, Enterobacter cloacae, Enterobacter aerogenes, Escherichia coli, Klebsiella, Proteus, Salmonella, Shigella, Vibrio, Yersinia, etc. Norfloxacin also has antibacterial activity against multi-drug resistant bacteria in vitro. IT also has good antibacterial effects Neisseria gonorrhoeae, Haemophilus influenzae and Moraxella catarrhalis which are resistant to penicillin. Norfloxacin is a bactericide, which inhibits DNA synthesis and replication by acting on the A subunit of bacterial DNA helicase, leading to bacterial death.

4. Pharmacokinetics

Oral absorption on an empty stomach is rapid but incomplete, only about 30%-40% of the dose can be absorbed; widely distributed in various tissues and body fluids, such as liver, kidney, lung, prostate, testis, uterus, bile, sputum, blisters, blood and urine, etc., but not seen in Central Nervous System.

The serum protein binding rate is 10% to 15%, the blood elimination half-life (t1/2) is 3 to 4 hours, and it can be prolonged to 6 to 9 hours when renal function declines. A single oral dose of 400mg and 800mg of the product, the plasma concentration reaches its peak value after 1 to 2 hours, and the peak plasma concentration (Cmax) is 1.4-1.6mg/L and 2.5mg/L respectively. The kidneys (glomerular filtration and renal tubular secretion) and hepatobiliary system are the main excretion pathways. 26%~32% are excreted in the urine in the original form and less than 10% are excreted in the form of metabolites, and bile and feces account for 28 %~30%.

Urine pH affects the solubility of norfloxacin. Urine dissolves least at pH 7.5, and increases at other pH value.

Norfloxacin Uses

1. Indications

  • Urogenital infections, including urinary tract infections, prostatitis, acute and chronic pyelonephritis, cystitis, gonorrhea, etc. Among them, suppositories and medicinal films are used for bacterial vaginitis caused by sensitive bacteria; pediatric powder is used for upper and lower urinary tract infections in children caused by multi-drug resistant bacteria that are only sensitive to this medicine.
  • Digestive system infections, gastrointestinal infections and cholecystitis caused by typhoid fever and other Salmonella species.
  • Respiratory tract infections, such as acute bronchitis, acute exacerbation of chronic bronchitis, and pneumonia.
  • It can also be used for infectious diseases in ENT, dermatology, obstetrics and surgery. Among them, eye drops or ointments are used for external eye infections (such as conjunctivitis, keratitis), trachoma, and neonatal acute follicular conjunctivitis caused by sensitive bacteria; subconjunctival injection or oral preparations can also be used to treat intraocular infection. The ointment is used for impetigo, eczema infection, tinea pedis infection, folliculitis, boils, etc. It can also control burn granulation wound infection and create conditions for skin grafting.
  • It can also be used as a preventive medication for abdominal surgery.

2. Uses

It has a good curative effect on gastroenteritis and bacillary dysentery caused by pathogenic and toxic Escherichia coli, Salmonella, etc., and is widely used in clinical practice and is well known to people. Norfloxacin is an anti-inflammatory drug, a broad-spectrum antibiotic.

The drug has high antibacterial activity against aerobic gram-negative bacilli, mainly against Citrobacter, Enterobacter aerogenes and other Enterobacter species, Escherichia coli, Klebsiella, Proteus, Salmonella, and Chi Yersinia spp. and is mainly used for infectious diseases such as urinary tract, intestinal tract, gynecology, otolaryngology, surgery and dermatology caused by sensitive bacteria with good anti-inflammatory effect. Do not use it for young children, pregnant women and those with severe liver and kidney dysfunction. The adverse reactions include gastrointestinal, central nervous system, allergies and other symptoms.

3. Dosage

  • Acute simple lower urinary tract infections caused by Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis 400 mg once, twice a day, for 3 days.
  • Simple urinary tract infections caused by other pathogens. The dose is the same as above, and the course of treatment is 7-10 days.
  • The dose for complicated urinary tract infections is the same as above, and the course of treatment is 10-21 days.
  • Simple gonococcal urethritis 800~1200mg per time.
  • Acute and chronic prostatitis 400mg once, twice a day, the course of treatment is 28 days.
  • Intestinal infection: 300~400mg once, 2 times a day, the course of treatment is 5-7 days.
  • Salmonella typhi infection: 800-1200 mg a day, divided into 2 to 3 times, the course of treatment is 14-21 days.

Norfloxacin side effects

On November 21, the State Food and Drug Administration issued the 58th "Adverse Drug Reaction Information Bulletin" to remind everyone to pay attention to the serious adverse reactions of fluoroquinolone antibiotics. Relevant data indicate that fluoroquinolone drugs have neuromuscular blocking activity, which may aggravate the symptoms of myasthenia in patients with myasthenia gravis; it can cause peripheral neuropathy, and peripheral neuropathy can occur quickly within a few days after medication, and may be irreversible; some fluoroquinolone drugs may affect the blood sugar control level of diabetic patients, and moxifloxacin has the highest risk.

Fluoroquinolones are a class of broad-spectrum antibiotics, which have a strong sterilization effect on aerobic gram-negative bacteria and good antibacterial activity against Staphylococcus aureus. The generic names of these drugs often have the word "floxacin", such as norfloxacin, pefloxacin, ofloxacin, levofloxacin, moxifloxacin, ciprofloxacin, and Mefloxacin, Fleroxacin, Enoxacin, Sparfloxacin, enrofloxacin, Clinfloxacin, Gatifloxacin, Rufloxacin, Tofloxacin, Nafloxacin, Sparfloxacin, Gemifloxacin, etc. Norfloxacin is a very common medicine, and many people use it to treat diarrhea. But there are some people who’d better not to take it.

  • Diabetes patients: Taking it can easily cause blood sugar fluctuations and hypoglycemia.

A study published in August analyzed the data of 78,000 diabetic patients receiving antibiotics in Taiwan and found that compared with macrolide antibiotics, diabetic patients who used fluoroquinolone had a higher rate of hypoglycemia and hyperglycemia. The report also specifically pointed out that among all fluoroquinolones, moxifloxacin has the greatest impact on the blood sugar control ability of diabetic patients, leading to the highest risk of hypoglycemia.

It is recommended that doctors consider these risks when prescribing fluoroquinolones to diabetic patients. If the patient develops nausea, vomiting, heart palpitations, sweating, paleness, hunger, transient syncope, etc. after taking the medicine, blood glucose disorders should be considered and seek medical attention in time.

  • Children: affects bone development

Because of the possibility of damage to bones, fluoroquinolones are generally not recommended for children. Although the instructions of many fluoroquinolone drugs state "prohibited under the age of 18", many parents still use norfloxacin and other drugs when their children have diarrhea, and even require doctors to prescribe such drugs. Studies have shown that quinolone drugs can damage the cartilage of weight-bearing joints and affect bone growth, which may affect the height of children. Similarly, pregnant women and breastfeeding women cannot take it.

  • Patients with myasthenia gravis: it can aggravate symptoms, which can be fatal

In 2004, the risk of fluoroquinolones that can cause peripheral neuropathy was written in the product manual. Recent domestic and foreign monitoring data indicate that this kind of disease may be irreversible, that is, it cannot be recovered after stopping the drug.

This kind of disease will occur soon after the use of fluoroquinolone drugs, usually within a few days, and some patients will continue to have symptoms for more than one year after the drug is stopped. If the patient has pain, burning sensation, tingling sensation, numbness, weakness or other sensory changes, such as light touch, pain, temperature, position, and vibration changes, it may indicate peripheral neuropathy, fluoroquinolone should be discontinued and changed in accordance with the doctor's advice.

1. Adverse Reactions

  • Gastrointestinal reactions are common and can be manifested as abdominal discomfort, pain, diarrhea, nausea or vomiting.
  • Central nervous system reactions: dizziness, headache, drowsiness or insomnia.
  • Allergic reactions, skin rash, itching, and occasional exudative erythema and angioedema. A few patients have photosensitivity.
  • Occasionally: epileptic seizures, mental disorders, irritability, disturbance of consciousness, hallucinations, tremors. Interstitial nephritis: hematuria, fever, and rash.
  • A small number of patients may have increased serum aminotransferase, increased blood urea nitrogen, and decreased peripheral blood white blood cells, most of which are mild and transient.

2. Warnings

  • Norfloxacin should be taken on an empty stomach with 250ml of water.
  • Because Escherichia coli is more resistant to norfloxacin, urine samples should be collected for culture before administration, and the medication should be adjusted according to the results of bacterial susceptibility.
  • Crystaluria may occur when norfloxacin is used in large doses or when the urine pH is above 7. In order to avoid the occurrence of crystaluria, it is advisable to drink more water and maintain a urine output above 1200ml.
  • For patients with impaired renal function, the dosage should be adjusted according to renal function.
  • Moderate to severe photosensitivity can occur with fluoroquinolones. Avoid excessive exposure to sunlight when applying norfloxacin. Stop the drug if photosensitivity occurs.
  • Patients with glucose-6-phosphate dehydrogenase deficiency who take norfloxacin may experience hemolysis in rare cases.
  • Quinolones, including norfloxacin, can cause symptoms of myasthenia gravis to be aggravated, respiratory muscle weakness which would be life-threatening. Patients with myasthenia gravis should be especially cautious when using quinolones.
  • When liver function declines, if it is severe (cirrhotic ascites), it can reduce drug clearance, blood concentration increases, and liver and kidney function decline is particularly obvious. It is necessary to weigh the pros and cons before application and adjust the dose.
  • Patients with pre-existing central nervous system diseases, such as those with a history of epilepsy, should avoid its application.

3. Norfloxacin Interactions

  • Urine alkalizer can reduce the solubility of the product in urine, leading to crystal urine and nephrotoxicity.
  • When norfloxacin is used in combination with theophylline, it may be due to the competitive inhibition of the binding site of cytochrome P450, resulting in a significant reduction in liver clearance of theophylline, prolonged blood elimination half-life (t1/2), and increased blood concentration. Symptoms of theophylline poisoning occur, such as nausea, vomiting, tremor, restlessness, agitation, convulsions, heart palpitations, etc. Therefore, the blood concentration of theophylline should be measured and the dose adjusted when combined.
  • The combined use of cyclosporine and the product can increase the blood concentration of the former. The blood concentration of cyclosporine must be monitored and the dose adjusted.
  • When norfloxacin is used together with the anticoagulant warfarin, it can enhance the anticoagulant effect of the latter, and the patient's prothrombin time should be closely monitored.
  • Probenecid can reduce the secretion of norfloxacin from the renal tubules by about 50%. When used in combination, it can cause toxicity due to the increased blood concentration of norfloxacin.
  • Norflxoacin has an antagonistic effect with nitrofurantoin, so combined application is not recommended.
  • Multivitamins, or other preparations containing iron and zinc ions, and antacids containing aluminum or magnesium can reduce the absorption of norfloxacin. It is recommended to avoid those combined use. If it is unavoidable, take norfloxacin 2 hours before or 6 hours after taking vitamins.
  • Didanosine (DDI) can reduce the oral absorption of norfloxacin. Because its preparation contains aluminum and magnesium, which can be chelated with fluoroquinolones, it is not suitable for combined use.


Norfloxacin belongs to the quinolone antibacterial drugs, which has antibacterial effect on many bacteria. Norfloxacin has a very good effect on diarrhea, and many families have such drugs. But it needs to be noted that children should not take norfloxacin, because norfloxacin can damage the bones of minors and may make the child grow slower.


BALLYA provides a ballya-norfloxacin-test to tell you if there are norfloxacin residues in chicken and honey.


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