Moderate
Azithromycin × Ketoconazole
Macrolides×Systemic antimycotics. Imidazole derivatives
Mechanism
Additive QT prolongation.
Symptoms
QT prolongation on ECG. Dizziness, syncope, palpitations. Rarely: 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. Alternative antibiotics: a cephalosporin or doxycycline (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.