Invasive aspergillosis (IA) is an opportunistic infection affecting immunocompromised patients. Current clinical guidelines support the use of voriconazole for the treatment of IA, although this treatment is not free of interactions in this group of patients who are often treated with polytherapy; in these cases, isavuconazole may be a safe alternative with a lower risk of interactions. The oral route is commonly preferred to the parenteral route, but in patients who do not have access to the enteral route, the use of isavuconazole is limited to the parenteral route only, since the technical information sheet does not recommend the handling of tablets for enteral administration, stating that the capsules should not be chewed, crushed, dissolved or opened. This paper presents the case of a patient with diffuse large B-cell lymphoma with confirmed AI on treatment with isavuconazole by enteral tube. It is detailed here that isavuconazole concentrations are maintained when administered by enteral tube, as measured by therapeutic pharmacokinetic monitoring of its plasma concentrations. Administering isavuconazole by enteral tube was found to be a safe practice with monitoring of its plasma concentrations.