Major
Haloperidol × Tramadol
First-generation antipsychotics. Butyrophenone derivatives×Other opioids
Mechanism
Tramadol lowers seizure threshold and prolongs QT. Haloperidol is a strong QT prolonger, especially parenterally. Additive seizure and torsades de pointes risk.
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. For analgesia on haloperidol, use paracetamol, an NSAID, or morphine/oxycodone. Alternative antipsychotics: olanzapine or aripiprazole.
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.