Sparfloxacin and astemizole can cause :
## **Core Concept**
The question pertains to the potential side effects of drug interactions, specifically involving the QT interval prolongation, which can lead to serious cardiac arrhythmias such as Torsades de Pointes. Sparfloxacin is a fluoroquinolone antibiotic, and astemizole is an antihistamine. Both classes of drugs are known to potentially affect cardiac electrophysiology.
## **Why the Correct Answer is Right**
Sparfloxacin, like other fluoroquinolones, and astemizole, an antihistamine that was withdrawn from many markets due to safety concerns, are both known to prolong the QT interval. The QT interval represents the time from the start of the Q wave to the end of the T wave in the heart's electrical cycle, reflecting the period of ventricular depolarization and repolarization. Prolongation of the QT interval can predispose to Torsades de Pointes, a potentially fatal arrhythmia. The concomitant use of drugs that prolong the QT interval increases the risk of this serious side effect.
## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is not specified, but if it does not relate to QT interval prolongation or Torsades de Pointes, it would be incorrect because the combination of sparfloxacin and astemizole is notably risky for cardiac effects.
- **Option B:** Similarly, without specifics, if this option does not align with the known side effects of these drugs (e.g., QT prolongation), it would be incorrect.
- **Option C:** If this option does not correctly identify the risk of QT interval prolongation or Torsades de Pointes associated with sparfloxacin and astemizole, it would be incorrect.
## **Clinical Pearl / High-Yield Fact**
A critical clinical pearl is that the concomitant use of drugs known to prolong the QT interval should be avoided. For fluoroquinolones like sparfloxacin, and antihistamines like astemizole, careful consideration of the patient's medication list and monitoring for signs of QT prolongation (e.g., palpitations, syncope) are crucial.
## **Correct Answer:** . Torsades de Pointes