MajorFirst-generation antipsychotics. Butyrophenone derivatives×Calcineurin inhibitor (immunosuppressant)
Updated · Methodology
Mechanism
Additive QT prolongation. Haloperidol strongly prolongs QT, especially parenterally (IV). Tacrolimus prolongs QT with hypomagnesaemia. Combined action raises 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, especially IV haloperidol. Alternative antipsychotics with minimal QT effect post-transplant: olanzapine or aripiprazole. For acute delirium: dexmedetomidine (no QT effect).
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.
Summary of a multi-drug list →
Medicine list: everything you take in one place →
Sources
- FDA: Haloperidol tablet (Ajanta Pharma USA Inc.) – Prescribing Information (2008)– ; DailyMed setid 31e33656-2f53-49e6-9816-261ea2e6961a
- AEMPS: Ficha técnica: Tacrolimus (nº registro 84607), sección 4.4 (2026)– AEMPS, CIMA, nº registro 84607, revisión 03/2026, sección 4.4