Fluoroquinolones

When should fluoroquinolones be used?

For serious infections or when other options are ineffective.

Why are fluoroquinolones not used routinely?

Due to rising resistance and significant side effects.

What genitourinary conditions are treated with fluoroquinolones?

Urinary tract infections and prostatitis.

What respiratory conditions may justify fluoroquinolone use?

Pneumonia and chronic bronchitis (if no alternatives).

What gastrointestinal condition is treated with fluoroquinolones?

Traveler’s diarrhea.

What types of infections beyond respiratory and GI are treated with fluoroquinolones?

Bone, joint, and skin infections.

What drug is first-line for Pseudomonas aeruginosa?

Ciprofloxacin.

Which bioterrorism-related disease is treated with ciprofloxacin?

Anthrax.

When are fluoroquinolones not recommended?

For acute sinusitis, bronchitis, or uncomplicated UTIs—if alternatives are available.

What is the mechanism of action of fluoroquinolones?

They inhibit bacterial DNA synthesis.

What enzyme do fluoroquinolones target in gram-negative bacteria?

DNA gyrase.

What enzyme do fluoroquinolones target in gram-positive bacteria?

Topoisomerase IV.

Why is inhibition of these enzymes lethal to bacteria?

It prevents DNA replication by blocking supercoiling relaxation.

Why are fluoroquinolones selectively toxic to bacteria?

Human cells do not have DNA gyrase or topoisomerase IV.

Should fluoroquinolones be used in children or pregnant women?

No, due to risk of cartilage damage and arthropathy.

Why should patients with myasthenia gravis avoid fluoroquinolones?

They can worsen muscle weakness.

What tendon-related condition is a contraindication for fluoroquinolones?

Tendon disorders, especially risk of Achilles tendon rupture.

Why should patients with cardiac arrhythmias avoid fluoroquinolones?

They can cause QT prolongation.

What enzyme does ciprofloxacin inhibit, leading to drug interactions?

CYP1A2.

Name drugs that interact with ciprofloxacin via CYP1A2 inhibition.

Theophylline, caffeine, clozapine.

Why are fluoroquinolones risky for patients with seizures or CNS disorders?

They can lower the seizure threshold.