Ketoconazole is a strong CYP3A4 inhibitor. Pimozide rises 8-fold, QT extends past 500 ms. FDA Orap Section 4.
Symptoms
Progressive QT prolongation within 5 days, torsades de pointes risk.
Management
Combination contraindicated. Alternative: terbinafine or fluconazole for limited infections (fluconazole is a weaker CYP3A4 inhibitor but still requires 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.