For an 85-year-old patient with a QTc of 570 milliseconds, what action should be taken regarding her ciprofloxacin therapy?

In an 85-year-old patient with a QTc interval of 570 milliseconds, there is a significant risk of developing life-threatening arrhythmias, particularly Torsades de Pointes. Ciprofloxacin belongs to the fluoroquinolone class of antibiotics, which can prolong the QT interval and exacerbate the risk for a patient already exhibiting QT prolongation.

Changing ciprofloxacin to nitrofurantoin is appropriate in this scenario because nitrofurantoin has a much lower propensity to cause QT prolongation, making it a safer alternative for treating urinary tract infections without compounding the patient’s existing risk.

While magnesium therapy can sometimes be used to prevent or treat arrhythmias associated with prolonged QT intervals, it does not address the underlying issue of having an antibiotic that further prolongs the QT interval. Continuing the current medication regimen would maintain the risk of QT prolongation, and discontinuing diltiazem does not directly mitigate the risk posed by ciprofloxacin in this context.

Thus, switching to nitrofurantoin represents a proactive approach to safeguarding the patient while still effectively managing their infection, demonstrating an understanding of both the pharmacological implications and the need for careful medication management in elderly patients with known cardiac risk factors.