Lascufloxacin-Induced QT Prolongation in an Elderly Patient Treated With Escitalopram: A Case Report

Lascufloxacin is a novel fluoroquinolone antibacterial agent for respiratory infection in Japanese geriatrics. Although QT prolongation is a known adverse effect of fluoroquinolones, to our knowledge, QT prolongation associated with lascufloxacin has never been reported. Escitalopram is a selective serotonin reuptake inhibitor used to treat senile depression and can cause QT prolongation. Elderly patients are particularly susceptible to QT prolongation because polymorbidity and polypharmacy are common in geriatrics. In this report, we describe a case of severe QTc prolongation in an 89-year-old female patient who was administered lascufloxacin with escitalopram. Severe QTc prolongation was observed on the third day of lascufloxacin therapy, although escitalopram had already been used before the initiation of lascufloxacin. The QTc interval improved beyond the patient's baseline on the fourth day after lascufloxacin and escitalopram were changed to oral minocycline and paroxetine, respectively. Healthcare practitioners should be alert to the risk of severe QT prolongation when co-administering lascufloxacin and escitalopram because these drugs are frequently prescribed in Japanese geriatrics. Careful electrocardiogram (ECG) monitoring is recommended when lascufloxacin and escitalopram are co-administered, particularly in elderly patients. Similar to this case, polypharmacy and medication safety are critical issues that should be addressed in Japanese geriatrics.