A 66-year-old woman with a history of torsades de pointes requires oral therapy for a multidrug-resistant Gram-negative infection. Which fluoroquinolone should be avoided because of the greatest risk of QT prolongation?
- A Norfloxacin
- B Moxifloxacin ✓
- C Ofloxacin
- D Ciprofloxacin
Correct answer: B. Moxifloxacin
Explanation
Among commonly used fluoroquinolones, moxifloxacin prolongs the QT interval more than ciprofloxacin, ofloxacin, or norfloxacin, and it is contraindicated in patients with known QT prolongation, uncorrected hypokalemia, or concurrent class Ia or III antiarrhythmics. Sparfloxacin was withdrawn largely for this reason. In such a patient, ciprofloxacin offers the least cardiac repolarization risk while retaining useful Gram-negative cover.
Reference: Katzung Basic and Clinical Pharmacology, 15th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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