An older adult taking amiodarone and glyburide receives a new levofloxacin prescription. Which nursing action is the priority before the first dose?
1Give levofloxacin with a magnesium antacid and schedule an ECG after the antibiotic course ends.
2Increase the glyburide dose and reduce carbohydrate intake throughout the antibiotic course.
3Add ondansetron for nausea and continue amiodarone without further cardiac assessment.
4Clarify the order because amiodarone adds QT risk, and arrange close glucose monitoring if levofloxacin is used.✓ Correct answer
Explanation
Levofloxacin should be avoided in clients receiving a class III antiarrhythmic such as amiodarone because both can prolong the QT interval. Fluoroquinolones can also cause hypo- or hyperglycemia, especially in clients taking an oral hypoglycemic such as glyburide. The nurse should clarify the order before the first dose and coordinate an alternative or a risk-mitigation plan. Magnesium antacids impair oral absorption, adding ondansetron can add QT risk, and glyburide should not be increased independently.
Clinical reasoning This prescription creates two hazards: additive QT prolongation from amiodarone and levofloxacin, and dysglycemia in a client taking glyburide.
Decision rule Clarify avoidable QT-risk combinations before the first dose; if levofloxacin remains necessary, follow the prescriber's ECG, electrolyte, and glucose-monitoring plan.
Fluoroquinolone QT risk — Levofloxacin can prolong ventricular repolarization and should be avoided with class IA or III antiarrhythmics and uncorrected hypokalemia.
Fluoroquinolone dysglycemia — Levofloxacin can cause symptomatic hypo- or hyperglycemia, particularly with insulin or an oral hypoglycemic such as glyburide.