Which SSRI has a documented risk of QT prolongation when used with ciprofloxacin?

• A. Sertraline
• B. Citalopram
• C. Paroxetine
• D. Fluoxetine

Answer: (B)

This item tests drug interaction risk for QT prolongation when an SSRI is used with a QT-prolonging antibiotic like ciprofloxacin. Citalopram has a well-documented, dose-dependent potential to prolong the QT interval. When combined with ciprofloxacin, which can also extend the QT interval, the risk of dangerous arrhythmias such as torsades de pointes increases. The other SSRIs—sertraline, paroxetine, and fluoxetine—do not have the same established association with QT prolongation, so they don’t carry this specific interaction risk with ciprofloxacin to the same extent. Therefore, the SSRI with the documented QT prolongation risk in this combination is citalopram. If such a combination is necessary, consider alternative antibiotics or adjusting the SSRI dose and monitor the patient for arrhythmia risk.