Major
Droperidol × Ondansetron
First-generation antipsychotic, butyrophenone. Used as antiemetic.×5-HT3 serotonin receptor antagonist
Mechanism
Additive QT prolongation (ondansetron 10-15 ms + droperidol 10-20 ms).
Symptoms
QTc above 500 ms, syncope, torsades de pointes risk.
Management
Choose one antiemetic or use ECG monitoring.
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.
Sources
- FDA: Inapsine (droperidol) prescribing information (2007)– FDA Inapsine label, boxed warning QT