CH4 | Quinolones and Fluoroquinolones

Question 1

What are the most common fluoroquinolones?

Answer 1

• Ciprofloxacin.
• Levofloxacin.
• Moxifloxacin.
• Nalidixic acid.
• Norfloxacin.
• Ofloxacin.

Question 2

How are fluoroquinolones classified?

Answer 2

Into four generations:
* 1st Generation: Nalidixic acid (protype).
* 2nd Generation: Ciprofloxacin.
* 3rd Generation: Levofloxacin.
* 4th Generation: Moxifloxacin, gemifloxacin, delafloxacin.

Question 3

What modifications were made to create fluoroquinolones?

Answer 3

Further modifications of the quinolone nucleus led to an expanded spectrum of activity, improved pharmacokinetics, and stability against common resistance mechanisms.

Question 4

Why did fluoroquinolones become 2nd line options for various indications?

Answer 4

Due to resistance to Gram-negative and Gram-positive organisms and increased frequency of C. difficile infections.

Question 5

What is the mechanism of action (MOA) of Quinolones and Fluoroquinolones?

Answer 5

They bind to and inhibit bacterial DNA gyrase and topoisomerase IV.

Question 6

What role does DNA gyrase play in bacterial replication?

Answer 6

It reduces torsional stress ahead of replicating forks by breaking double-strand DNA.

Question 7

What is the function of topoisomerase IV in bacterial cells?

Answer 7

It separates daughter chromosomes once replication is completed.

Question 8

How do Fluoroquinolones lead to rapid cell death?

Answer 8

By interfering with DNA ligation.

Question 9

What types of organisms do quinolones and fluoroquinolones target?

Answer 9

Gram-positive and Gram-negative organisms, as well as anaerobic organisms.

Question 10

What infections is Ciprofloxacin commonly used to treat?

Answer 10

Anthrax, urinary tract infections (UTIs), gastrointestinal infections, traveler’s diarrhea, and typhoid fever.

Question 11

What are the clinical uses of Levofloxacin?

Answer 11

Urinary tract infections (UTIs) and community-acquired respiratory infections, including pneumonia.

Question 12

Which fluoroquinolone is effective against anaerobic infections?

Answer 12

Moxifloxacin.

Question 13

What infections is Moxifloxacin used to treat?

Answer 13

Anaerobic infections and community-acquired respiratory infections, including pneumonia.

Question 14

What is Gemifloxacin primarily used for?

Answer 14

Community-acquired respiratory infections.

Question 15

What are the resistance mechanisms to fluoroquinolones?

Answer 15

• Altered binding target.
• Decreased accumulation by modifying permeability and efflux pumps.
• Enzymatic degradation, such as in the case of actylation.

Question 16

How are quinolones and fluoroquinolones absorbed after oral administration?

Answer 16

They are well absorbed.

Question 17

Which fluoroquinolones have the highest bioavailability?

Answer 17

Levofloxacin and moxifloxacin.

Question 18

What substances can interfere with the absorption of fluoroquinolones?

Answer 18

Al- or Mg-containing antacids, Fe or Zn containing supplements, and Ca and other divalent cations.

Question 19

How do fluoroquinolones distribute in the body?

Answer 19

They distribute well into all tissues and body fluids.

Question 20

Where do fluoroquinolones achieve high concentrations?

Answer 20

In bone, urine (except moxifloxacin), kidney, prostatic tissue, and lungs.

Question 21

Do fluoroquinolones penetrate into the central nervous system?

Answer 21

Yes, they penetrate into CSF and are considered in certain CNS infections.

Question 22

How is Moxifloxacin primarily metabolized?

Answer 22

By the liver.

Question 23

How are Fluoroquinolones primarily eliminated from the body?

Answer 23

They are excreted renally.

Question 24

What are common adverse reactions associated with Quinolones and Fluoroquinolones?

Answer 24

Nausea, vomiting, diarrhea, headache, dizziness, tendinitis, tendon rupture, peripheral neuropathy, phototoxicity, arrhythmia, and drug-drug interactions.

Question 25

What central nervous system effects can occur with Fluoroquinolone use?

Answer 25

Hallucinations, anxiety, insomnia, confusion, seizures, and peripheral neuropathy.