Isavuconazonium, sold under the brand name Cresemba, is a systemic antifungal medication of the triazole class which is used to treat invasive aspergillosis and mucormycosis.

[9] The most common side effects include abnormal liver tests, nausea, vomiting, difficulty breathing, abdominal pain, diarrhea, injection site reactions, headache, low blood potassium and skin rash.

[7][8][9] Common adverse effects (occurring in between 1 and 10% of people) include low potassium, decreased appetite, delirium, headache, sleepiness, vein inflammation, difficulty breathing, acute respiratory failure, vomiting, diarrhea, nausea, stomach pain, elevated results in liver function tests, rash, itchy skin, kidney failure, chest pain, and fatigue.

[7][8] After oral or intravenous administration, isavuconazonium is rapidly hydrolysed by esterases in blood or the gastrointestinal tract to the active form, isavuconazole.

Mammalian cells are resistant to demethylation inhibition by azoles, making the drug effects specific to fungi.

In February 2010, Basilea partnered with Astellas Pharma to complete Phase III trials, obtain regulatory approvals, and market the drug.