Fluoroquinolones Classification and Mechanisms

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Questions and Answers

Which of the following are considered Quinolones?

  • Nalidixic acid
  • Ciprofloxacin
  • Norfloxacin
  • All of the above (correct)

Which of the following Quinolones is only effective against gram-negative bacteria?

  • Ciprofloxacin
  • Nalidixic acid (correct)
  • Moxifloxacin
  • Norfloxacin

Which of the following Quinolones is considered to have the least activity against both gram-negative and gram-positive bacteria?

  • Ciprofloxacin
  • Ofloxacin
  • Norfloxacin (correct)
  • Moxifloxacin

Which of the following Quinolones is considered to have excellent activity against both gram-negative and gram-positive bacteria?

<p>Moxifloxacin (C)</p> Signup and view all the answers

Quinolones are bactericidal.

<p>True (A)</p> Signup and view all the answers

Quinolones block bacterial DNA synthesis by inhibiting ______ II (DNA gyrase) and topoisomerase IV.

<p>topoisomerase</p> Signup and view all the answers

Which of the following are mechanisms of resistance to Quinolones?

<p>All of the above (D)</p> Signup and view all the answers

Which of the following bacteria are susceptible to Quinolones?

<p>All of the above (D)</p> Signup and view all the answers

Which of the following is NOT a common adverse drug reaction associated with Quinolones?

<p>Hepatic system (D)</p> Signup and view all the answers

Quinolones are contraindicated in pregnancy and lactation.

<p>True (A)</p> Signup and view all the answers

Which of the following Quinolones is indicated for the treatment of gonorrhoea?

<p>Ciprofloxacin (C)</p> Signup and view all the answers

Which of the following Quinolones is considered to be more active against gram-negative bacteria, including Chlamydia?

<p>Lomefloxacin (A)</p> Signup and view all the answers

Which of the following Quinolones is considered to be more active against gram-positive bacteria, including Streptococcus pneumoniae?

<p>Sparfloxacin (C)</p> Signup and view all the answers

Which of the following Quinolones has been discontinued in the United States and United Kingdom due to adverse reactions?

<p>Gatifloxacin (B)</p> Signup and view all the answers

Which of the following Quinolones is indicated for the treatment of community-acquired pneumonia?

<p>Levofloxacin (D)</p> Signup and view all the answers

Which of the following Quinolones can be administered intravenously?

<p>All of the above (D)</p> Signup and view all the answers

Nalidixic acid can be administered intravenously.

<p>False (B)</p> Signup and view all the answers

Which of the following Quinolones can be administered as eye drops?

<p>All of the above (D)</p> Signup and view all the answers

Sparfloxacin can be administered intravenously.

<p>False (B)</p> Signup and view all the answers

Flashcards

Quinolones

A class of antibiotics that inhibit bacterial DNA synthesis by blocking the action of topoisomerase II (DNA gyrase) and topoisomerase IV.

Fluoroquinolones

A subclass of quinolones that are more potent and have a broader spectrum of activity against both gram-negative and gram-positive bacteria.

Norfloxacin

A common fluoroquinolone used to treat urinary tract infections, bacterial diarrhea, and some respiratory infections.

Ciprofloxacin

A fluoroquinolone known for its effectiveness against a wide range of bacteria, including those that are resistant to other antibiotics.

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Levofloxacin

A fluoroquinolone with excellent activity against Streptococcus pneumoniae and other respiratory pathogens. It's often used for community-acquired pneumonia.

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Lomefloxacin

A fluoroquinolone similar to ciprofloxacin, but shows enhanced activity against gram-negative bacteria and Chlamydia.

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Sparfloxacin

A fluoroquinolone with a long half-life, allowing for single-dose administration. It's effective against a wide range of bacteria, including gram-positive and some anaerobic bacteria.

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Gatifloxacin

A fluoroquinolone with excellent activity against Streptococcus pneumoniae and other respiratory pathogens. It's commonly used for community-acquired pneumonia and exacerbations of chronic bronchitis.

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Moxifloxacin

A fluoroquinolone with a broad spectrum of activity against both gram-positive and gram-negative bacteria. It's especially effective against Streptococcus pneumoniae , Mycoplasma , Chlamydia , some anaerobic bacteria , and those resistant to other antibiotics.

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Chromosomal mutation

A mechanism of resistance where bacteria develop mutations in their genes, leading to alterations in the target enzymes like DNA gyrase and topoisomerase IV. This prevents quinolones from binding effectively.

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Reduced permeability

A mechanism where bacteria reduce their permeability to quinolones, making it harder for the drug to enter the cell.

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Increased efflux

A mechanism where bacteria actively pump out the quinolone drug before it can reach its target, preventing its effect.

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Bactericidal

The ability of a drug to kill bacteria directly.

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Oral administration

A common route of administration for many fluoroquinolones, allowing the drug to be absorbed into the bloodstream through the digestive system.

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Intravenous infusion

A method of delivering the drug directly into a vein, offering faster absorption and higher drug levels in the blood.

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Eye drops

A topical route of administration for some fluoroquinolones, allowing treatment of infections in the eye.

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Ear drops

A topical route of administration for some fluoroquinolones, offering treatment for infections in the ear.

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Broad spectrum activity

The ability of a drug to affect a wide range of bacterial species, including both gram-negative and gram-positive bacteria.

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Urinary tract infection (UTI)

A type of bacterial infection that typically affects the urinary tract, including the bladder, urethra, and kidneys.

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Respiratory tract infection (RTI)

A type of infection that affects the lungs and respiratory system.

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Otitis media

A type of infection that affects the ears, particularly the middle ear.

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Sinusitis

A type of infection that affects the sinuses, the air-filled cavities in the skull.

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Septicemia

A serious bacterial infection that can cause fever, chills, and rapid heart rate.

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Meningitis

An infection affecting the protective membranes surrounding the brain and spinal cord.

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Dermatitis

A skin condition that involves the rapid growth of bacteria on the skin, causing redness, itching, and blisters.

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Streptococcus pneumoniae

A type of bacteria that can cause pneumonia and other respiratory infections.

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Campylobacter jejuni

A type of bacteria that can cause diarrhea and other gastrointestinal infections.

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Neisseria gonorrhoeae

A type of bacteria that can cause gonorrhea, a sexually transmitted infection.

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Neisseria meningitidis

A type of bacteria that can cause meningitis, especially in children.

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Escherichia coli

A type of bacteria that can cause infections of the urinary tract, lungs, and other areas.

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Study Notes

Fluoroquinolones

  • Fluoroquinolones are a class of antibacterial medications
  • Classified into three groups based on their activity against gram-negative and gram-positive bacteria.
  • Nalidixic acid shows excellent activity against only gram-negative bacteria.
  • Norfloxacin has minimal activity against both gram-negative and gram-positive bacteria.
  • Ciprofloxacin, Levofloxacin, Ofloxacin, Pazufloxacin, Pefloxacin, Lomefloxacin, Sparfloxacin, Moxifloxacin, Gemifloxacin, Prulifloxacin, Gatifloxacin, and Delafloxacin demonstrate great activity against gram-negative and moderate activity against gram-positive bacteria.
  • Some, like Moxifloxacin, also show excellent activity against anaerobic gram-negative rods.
  • Newer medications include Gatifloxacin and Delafloxacin.

Mechanism of action

  • Fluoroquinolones are bactericidal
  • They inhibit bacterial DNA synthesis by blocking topoisomerases II (DNA gyrase) and IV.

Mechanism of Resistance

  • Chromosomal mutations
  • Reduced permeability
  • Increased efflux

Antimicrobial Spectrum

Gram-negative bacteria

  • Escherichia coli, Salmonella typhi, Shigella, Enterobacter, Campylobacter jejuni, Vibrio cholerae, Neisseria gonorrhoeae, Neisseria meningitidis, Pseudomonas aeruginosa, Moraxella catarrhalis, Brucella, Klebsiella pneumoniae, Haemophilus influenzae, ducreyi, Legionella, Proteus, Yersinia enterocolitica, Serratia

Gram-positive bacteria

  • Streptococci, Staphylococci, Enterococci, Pneumococci, Bacteroides fragilis, Mycoplasma, Mycoplasma pneumoniae, Chlamydia, Chlamydia pneumoniae, trachomatis, Rickettsiae

Adverse Drug Reactions

  • Gastrointestinal tract issues
  • Central nervous system problems
  • Skin reactions
  • Tendon and cartilage damage
  • Cardiovascular System (CVS) complications
  • Blood glucose disturbances
  • Drug interactions

Contraindications

  • Pregnancy
  • Lactation
  • Pediatric age

Therapeutic Uses of Ciprofloxacin

  • Dental uses
  • Genitourinary tract infections
  • Gastrointestinal tract infections
  • Respiratory tract infections
  • ENT infections
  • Typhoid
  • Bone, soft tissues, gynaecological, and wound infections
  • Tuberculosis
  • Gram-negative septicaemias
  • Meningitis
  • Prophylaxis
  • Conjunctivitis
  • STD: Gonorrhoea, Chancroid.

Therapeutic Uses of Norfloxacin

  • Genitourinary tract infections
  • Bacterial diarrhea

Therapeutic Uses of Pefloxacin

  • Meningeal infections
  • Genitourinary tract infections
  • Gastrointestinal infections
  • Systemic infections
  • Typhoid
  • Gram-positive cocci & Listeria

Therapeutic Uses of Ofloxacin

  • Similar to Ciprofloxacin, suitable for leprosy, less interaction with theophylline
  • High oral bioavailability
  • Single dose
  • Community-acquired pneumonia
  • Exacerbation of chronic bronchitis

Therapeutic Uses of Levofloxacin

  • Similar to Ciprofloxacin
  • High activity against Streptococcus pneumoniae
  • Good oral bioavailability
  • Single dose
  • No drug interactions
  • Community-acquired pneumonia
  • Exacerbation of chronic bronchitis

Therapeutic Uses of Lomefloxacin

  • Similar to Ciprofloxacin
  • More active against gram-negative bacteria, Chlamydia
  • No interaction with theophylline
  • Single dose

Therapeutic Uses of Sparfloxacin

  • More active against gram-positive bacteria (Streptococcus pneumoniae, Staphylococcus, Enterococcus, Bacteroides fragilis, mycobacteria)
  • Indications include pneumonia, chronic bronchitis, sinusitis, tuberculosis, MAC-AIDS patients, leprosy, Chlamydial infections
  • Single dose

Therapeutic Uses of Gatifloxacin

  • Excellent activity against Streptococcus pneumoniae, some anaerobes, atypical respiratory pathogens including Chlamydia pneumoniae, M. tuberculosis
  • Community-acquired pneumonia
  • Exacerbation of chronic bronchitis & other RTIs
  • Potential adverse effects include tachycardia, prolonged QTc interval, phototoxicity, CNS effects, swelling over the face, Torsades de pointes, changes in blood glucose levels, and discontinuation in some regions

Therapeutic Uses of Moxifloxacin

  • Excellent activity against Streptococcus pneumoniae and beta-lactam/macrolide-resistant gram-positive bacteria
  • Primary indications include pneumonia, bronchitis, otitis media, and sinusitis

Routes of Administration

  • Nalidixic acid (oral)
  • Ciprofloxacin (oral, IV infusion, eye drops, ointment, ear drops)
  • Norfloxacin (oral, eye drops)
  • Levofloxacin (oral, IV infusion, eye drops, ear drops)
  • Ofloxacin (oral, IV infusion, eye drops, ear drops)
  • Pefloxacin (oral, IV infusion, eye drops)
  • Lomefloxacin (oral, eye drops)
  • Sparfloxacin (oral)
  • Moxifloxacin (oral, IV infusion, eye drops)
  • Gemifloxacin (oral, IV infusion, eye drops)
  • Gatifloxacin (oral, IV infusion, eye drops)

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