Major
Dronedarone × Haloperidol
Class III antiarrhythmic×First-generation antipsychotics. Butyrophenone derivatives
Mechanism
Additive QT prolongation. Torsades de pointes has been reported with dronedarone plus other QT-prolonging drugs. Haloperidol is particularly dangerous parenterally (IV).
Symptoms
QT prolongation on ECG. Dizziness, syncope, palpitations. Severe cases: polymorphic ventricular tachycardia (torsades de pointes). Risk is higher with hypokalaemia and hypomagnesaemia.
Management
Avoid the combination, especially IV haloperidol. Alternative antipsychotics with minimal QT effect: olanzapine or aripiprazole. For acute delirium: dexmedetomidine.
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.