Moderate
Amitriptyline × Fluconazole
Tricyclic antidepressants (TCA)×Antifungals, triazole derivatives
Mechanism
Fluconazole weakly blocks CYP2C19 and CYP3A4 – amitriptyline metabolic routes. TCA plasma levels may rise with prolonged fluconazole courses.
Symptoms
Worsening anticholinergic symptoms (dry mouth, constipation, urinary retention), drowsiness, tachycardia. QT prolongation on ECG at fluconazole doses ≥200 mg.
Management
For short fluconazole courses (up to 7 days), no special adjustment. For prolonged systemic therapy (>14 days), reduce amitriptyline by 25% temporarily. Alternative antifungals: terbinafine for dermatophytosis or echinocandins.
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.