Key result
Concomitant cisapride and CYP3A4 inhibitors linked to QT prolongation and syncope in a case report.
Why the study?
QT prolongation and syncopal episodes resulting from concomitant use of cisapride and agents inhibiting its metabolism had not been previously reported in the English-language literature.
Does concomitant use of cisapride and CYP3A4 inhibitors cause QT prolongation and syncope?
Case Report (n=1)
Does concomitant use of cisapride and CYP3A4 inhibitors cause QT prolongation and syncope?
Concomitant use of cisapride and CYP3A4 inhibitors like clarithromycin can lead to elevated cisapride levels, resulting in potentially fatal QT prolongation and syncope.
Warrants vigilance for QT prolongation with cisapride plus CYP3A4 inhibitors; leaves open confirmation in controlled studies.
OBJECTIVE: To report a case of QT prolongation and syncopal episodes resulting from concomitant use of cisapride and agents known to inhibit its metabolism. CASE SUMMARY: A 53-year-old white woman was involved in two motor vehicle accidents on the same day after experiencing syncopal episodes. Cardiac and neurologic evaluations were negative; the syncopal episodes were attributed to QT prolongation associated with the concomitant use of cisapride and agents known to inhibit its metabolism. DISCUSSION: This is the first case published in the English-language literature describing QT prolongation resulting from the concomitant use of cisapride and agents known to inhibit its metabolism. Clarithromycin inhibits CYP3A4, the isoenzyme responsible for the metabolism of cisapride. Concomitant administration of cisapride with agents known to inhibit CYP3A4 (i.e., azole antifungals, erythromycin, clarithromycin) may result in elevated cisapride concentrations. Elevated cisapride concentrations have been associated with QT prolongation, syncopal episodes, and cardiac dysrhythmias. CONCLUSIONS: Acquired QT prolongation is a well-recognized adverse effect of several drugs. Recognition of newer drugs and drug combinations that place patients at risk for this potentially fatal adverse event is imperative for appropriate monitoring and prevention.
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Vanessa Seals Gray (1998) conducted a case report in QT prolongation and syncopal episodes (n=1). Concomitant use of cisapride and CYP3A4 inhibitors was evaluated on QT prolongation and syncopal episodes. Concomitant use of cisapride and CYP3A4 inhibitors resulted in QT prolongation and syncopal episodes in a 53-year-old woman.
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