MajorSSRI (selective serotonin reuptake inhibitor)×Systemic antimycotics. Imidazole derivatives
Updated · Methodology
Mechanism
Ketoconazole is a potent CYP3A4 inhibitor. Effect on citalopram is moderate (CYP3A4 is a minor route), but ketoconazole itself prolongs QT, so additive torsades de pointes risk persists.
Symptoms
QT prolongation on ECG. Clinically: dizziness, syncope, palpitations. Severe cases progress to polymorphic ventricular tachycardia (torsades de pointes). Risk is higher with hypokalaemia, hypomagnesaemia, bradycardia, and ischaemic heart disease.
Management
Avoid the combination. Alternative antifungals: terbinafine for dermatophytosis or echinocandins for systemic mycoses. If ketoconazole is needed: ECG before start and at day 3 of therapy.
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: Ketoconazole tablet (Amerisyn LLC) – Prescribing Information (2014)– ; DailyMed setid 1d598696-c6f3-4b7c-ad73-949d2089df35