CriticalMacrolide antibiotic×First-generation antipsychotic, diphenylbutylpiperidine derivative
Updated · Methodology
Mechanism
Erythromycin is a moderate-to-strong CYP3A4 inhibitor. Pimozide concentration rises 3–5 fold, with additive QT prolongation (erythromycin itself is a QT prolonger). FDA Orap Section 4 contraindication.
Symptoms
QT prolongation, syncope, torsades de pointes within 3–10 days.
Management
Combination contraindicated. Alternative: azithromycin or another class. If erythromycin is needed, hold pimozide for the course.
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: Pimozide tablet (Par Health USA, LLC) – Prescribing Information (2011)– FDA Orap label, Section 4 Contraindications; DailyMed setid 70b079e2-a1f7-4a93-8685-d60a4d7c1280
- AEMPS: Ficha técnica: Eritromicina (nº registro 79380), sección 4.3 (2025)– AEMPS, CIMA, nº registro 79380, sección 4.3