A client receiving levofloxacin for a urinary tract infection presents with which finding that requires immediate attention?

Levofloxacin, a fluoroquinolone antibiotic used to treat various infections including urinary tract infections, can have significant effects on the cardiovascular system, particularly concerning its potential to cause a prolonged QT interval. A prolonged QT interval can lead to potentially life-threatening arrhythmias, such as Torsades de Pointes, which may result in syncope or sudden cardiac arrest. Therefore, if a patient presents with an electrocardiogram showing a prolonged QT interval while on levofloxacin, it is a finding that necessitates immediate clinical intervention to ensure the safety of the patient.

In contrast, elevated blood pressure may be concerning but is less immediate compared to the risks associated with cardiac arrhythmias linked to a prolonged QT interval. Discoloration of urine is a known side effect of levofloxacin but does not pose an urgent threat to the patient’s health. Severe headaches may occur as a side effect but are not as critical as the cardiac issues associated with the prolonged QT interval. Hence, monitoring and addressing the QT interval is paramount in the context of levofloxacin treatment.