chemistry

Norfloxacin

Norfloxacin is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Norfloxacin rather than just read about it. In short: Norfloxacin, sold under the brand name Noroxin among others, is an antibiotic that belongs to the class of fluoroquinolone antibiotics. It is used to treat urinary tract infections, gynecological infections, inflammation of the prostate gland, gonorrhea and bladder infection.

Key takeaways

Norfloxacin belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Norfloxacin to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Norfloxacin from memory before moving on to harder problems.

Reference excerpt

Norfloxacin, sold under the brand name Noroxin among others, is an antibiotic that belongs to the class of fluoroquinolone antibiotics. It is used to treat urinary tract infections, gynecological infections, inflammation of the prostate gland, gonorrhea and bladder infection. Eye drops were approved for use in children older than one year of age. Norfloxacin is associated with a number of rare serious adverse reactions as well as spontaneous tendon ruptures and irreversible peripheral neuropathy. Tendon problems may manifest long after therapy had been completed and in severe cases may result in lifelong disabilities. It was patented in 1977 and approved for medical use in 1983.

Medical uses The initial approval by the U.S. Food and Drug Administration (FDA) in 1986 encompassed the following indications:

Uncomplicated urinary tract infections (including cystitis) Complicated urinary tract infections (restricted use) Uncomplicated urethral and cervical gonorrhea (however this indication is no longer considered to be effective by some experts due to bacterial resistance) Prostatitis due to Escherichia coli. Syphilis treatment: Norfloxacin has not been shown to be effective in the treatment of syphilis. Antimicrobial agents used in high doses for short periods of time to treat gonorrhea may mask or delay the symptoms of incubating syphilis. Although fluoroquinolones are sometimes used to treat typhoid and paratyphoid fever, norfloxacin had more clinical failures than the other fluoroquinolones (417 participants, 5 trials). In ophthalmology, Norfloxacin licensed use is limited to the treatment of conjunctival infections caused by susceptible bacteria. Norfloxacin has been restricted in the Republic of Ireland due to the risks of C. difficile super infections and permanent nerve as well as tendon injuries. Its licensed use in acute and chronic complicated kidney infections has been withdrawn as a result. The European Medicines Agency, also in 2008, had recommended restricting the use of oral norfloxacin to treat urinary infections. CHMP had concluded that the marketing authorizations for norfloxacin, when used in the treatment of acute or chronic complicated pyelonephritis, should be withdrawn because the benefits do not outweigh their risks in this indication. CHMP stated that doctors should not prescribe oral norfloxacin for complicated pyelonephritis and should consider switching patients already taking oral norfloxacin for this type of infection to an alternative antibiotic. Norfloxacin is used for prevention of spontaneous bacterial peritonitis in cirrhotic patients who have a low ascites fluid protein level, impaired renal function, severe liver disease, have had a prior episode of spontaneous bacterial peritonitis, or esophageal variceal bleeding. Note: Norfloxacin may be licensed for other uses, or restricted, by the various regulatory agencies worldwide.

Contraindications As noted above, under licensed use, norfloxacin is also now considered to be contraindicated for the treatment of certain sexually transmitted diseases by some experts due to bacterial resistance. Norfloxacin is contraindicated in those with a history of tendonitis, tendon rupture and those with a hypersensitivity to fluoroquinolones. There are three contraindications found within the 2008 package insert:

"Noroxin (norfloxacin) is contraindicated in persons with a history of hypersensitivity, tendinitis, or tendon rupture associated with the use of norfloxacin or any member of the quinolone group of antimicrobial agents." "Quinolones, including norfloxacin, have been shown in vitro to inhibit CYP1A2. Concomitant use with drugs metabolized by CYP1A2 (e.g., caffeine, clozapine, ropinirole, tacrine, theophylline, tizanidine) may result in increased substrate drug concentrations when given in usual doses. Patients taking any of these drugs concomitantly with norfloxacin should be carefully monitored." "Concomitant administration with tizanidine is contraindicated" Norfloxacin is also considered to be contraindicated within the pediatric population.

Pregnancy Norfloxacin has been reported to rapidly cross the blood-placenta and blood-milk barrier, and is extensively distributed into the fetal tissues. For this reason norfloxacin and other fluoroquinolones are contraindicated during pregnancy due to the risk of spontaneous abortions and birth defects. The fluoroquinolones have also been reported as being present in the mother's milk and are passed on to the nursing child, which may increases the risk of the child having an adverse reaction even though the child had never been prescribed or taken any of the drugs found within this class. As safer alternatives are generally available norfloxacin is contraindicated during pregnancy, especially during the first trimester. The manufacturer only recommends use of norfloxacin during pregnancy when benefit outweighs risk.

Children A 1998 retrospective survey found that numerous side effects have been recorded in reference to the unapproved use of norfloxacin in the pediatric population. Fluoroquinolones are not licensed by the FDA for use in children due to the risk of fatalities as well as permanent injury to the musculoskeletal system, with two exceptions. Ciprofloxacin is being licensed for the treatment of Complicated Urinary Tract Infections and Pyelonephritis due to Escherichia coli and Inhalational Anthrax (post-exposure) and levofloxacin was recently licensed for the treatment of Inhalational Anthrax (post-exposure). However, the Fluoroquinolones are licensed to treat lower respiratory infections in children with cystic fibrosis in the UK.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Norfloxacin

Start with the simplest possible case. Write down what Norfloxacin claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Norfloxacin before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Norfloxacin ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Norfloxacin

In research: Norfloxacin appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Norfloxacin in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Norfloxacin is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1,4-di-hydro-7-(1-piperazinyl)-4-oxo-3-quinolinecarboxylic acids, 1-Piperazinyl compounds, CYP3A4 inhibitors, so understanding it makes those chapters shorter.
In everyday life: Look for Norfloxacin outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Norfloxacin in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Norfloxacin means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Norfloxacin out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Norfloxacin in simple terms?

Why does Norfloxacin matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Norfloxacin?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Norfloxacin.