Antifungal azoles with anti-filamentous activity (itraconazole, voriconazole, posaconazole, isavuconazole) are widely used in the hematol. ward for prophylaxis and treatment of invasive fungal infections. However, their gut absorption is very variable, their metabolism is complex and they are associated with drug-drug interactions. Therapeutic drug monitoring is recommended for optimizing the clin. efficacy and reducing drug-related adverse events, both in prophylactic and therapeutic indications.