Which safety concern is most associated with combining erythromycin with citalopram?

Which safety concern is most associated with combining erythromycin with citalopram?

• A. Hypertension
• B. Hypotension
• C. QT prolongation and risk of arrhythmia
• D. Kidney injury

Answer: (C)

This question tests a safety issue from a drug–drug interaction that affects the heart’s electrical activity. Erythromycin can prolong the QT interval by impacting ventricular repolarization, and citalopram also has a known potential to prolong QT, especially at higher doses. When used together, their effects on the heart’s repolarization can add up, increasing the risk of a dangerous rhythm disturbance called torsades de pointes, which can lead to fainting, seizures, or sudden death. That’s why the main safety concern is QT prolongation and the associated risk of arrhythmia. This is not primarily about blood pressure changes or kidney injury, which are not the key risks with this combination. In practice, avoid pairing these drugs or monitor closely and correct any electrolyte abnormalities if continuation is necessary.

This question tests a safety issue from a drug–drug interaction that affects the heart’s electrical activity. Erythromycin can prolong the QT interval by impacting ventricular repolarization, and citalopram also has a known potential to prolong QT, especially at higher doses. When used together, their effects on the heart’s repolarization can add up, increasing the risk of a dangerous rhythm disturbance called torsades de pointes, which can lead to fainting, seizures, or sudden death. That’s why the main safety concern is QT prolongation and the associated risk of arrhythmia. This is not primarily about blood pressure changes or kidney injury, which are not the key risks with this combination. In practice, avoid pairing these drugs or monitor closely and correct any electrolyte abnormalities if continuation is necessary.