Drug Interaction Report

MONITOR: Coadministration with inducers of CYP450 3A4 may decrease the plasma concentrations of isavuconazole, which is primarily metabolized by CYP450 3A4 and 3A5 and subsequently by uridine diphosphate glucuronosyltransferases (UGT). When multiple doses of isavuconazonium sulfate (prodrug of isavuconazole) were administered to healthy volunteers with multiple doses of the potent CYP450 3A4 inducer rifampin (600 mg), mean isavuconazole peak plasma concentration (Cmax) and systemic exposure (AUC) decreased by 75% and 97%, respectively. The extent to which other, less potent inducers of CYP450 3A4 may interact with isavuconazole is unknown.

MANAGEMENT: Caution is advised during concomitant use of isavuconazonium sulfate with CYP450 3A4 inducers. The potential for decreased efficacy of isavuconazonium sulfate should be considered.

MONITOR: Isolated case reports have suggested that the ingestion of alcohol during griseofulvin therapy may rarely cause disulfiram-like reactions, flushing, tachycardia, or increased effects of alcohol. The mechanism is unknown.

MANAGEMENT: Patients should be advised of the possibility of increased adverse effects or a disulfiram-like reaction.

The recommended maximum number of medicines in the 'antifungal agents' category to be taken concurrently is usually one. Your list includes two medicines belonging to the 'antifungal agents' category:

• Grisactin 250 (griseofulvin)
• isavuconazonium

Note: In certain circumstances, the benefits of taking this combination of drugs may outweigh any risks. Always consult your healthcare provider before making changes to your medications or dosage.