Fluoroquinolones

A 62-year-old man with chronic kidney disease (eGFR 25 mL/min) presents with acute exacerbation of chronic bronchitis due to Haemophilus influenzae. Which fluoroquinolone is best avoided in this patient, and what is the distinguishing toxicity concern?

A 42-year-old woman from Mumbai with a history of myasthenia gravis presents with acute exacerbation of symptoms: ptosis, diplopia, and generalized muscle weakness. She was empirically started on ciprofloxacin 500 mg twice daily 2 days ago for a suspected respiratory tract infection. Her symptoms have worsened significantly since starting the antibiotic. Neurological examination confirms worsening of ocular and bulbar signs. What is the mechanism by which this fluoroquinolone is likely exacerbating her myasthenia gravis?

A 42-year-old woman with uncomplicated urinary tract infection caused by Escherichia coli (susceptible to all fluoroquinolones) presents for outpatient management. Which fluoroquinolone is the drug of choice for empiric treatment of uncomplicated cystitis?

Which of the following is the primary mechanism of action of fluoroquinolones?

A 58-year-old man with chronic obstructive pulmonary disease presents with acute exacerbation characterized by purulent sputum, fever, and productive cough. Sputum culture is pending. Which fluoroquinolone is the drug of choice for empiric treatment of this acute exacerbation of chronic bronchitis?