Major
Fluconazole × Rifampicin
Antifungals, triazole derivatives×Antituberculous antibiotic
Mechanism
Rifampicin strongly induces CYP3A4, which partly metabolises fluconazole. Fluconazole plasma levels fall by 25%; antifungal efficacy decreases.
Symptoms
Recurrence of mycosis symptoms: ongoing fever, skin or mucosal lesions; in immunocompromised patients, risk of systemic mycosis progression.
Management
When combined, increase fluconazole by 50–100% with efficacy monitoring. Alternative antifungal during anti-TB therapy: echinocandins (micafungin, caspofungin; no CYP3A4 dependence).
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.