What the FDA labels say about taking them together
Isavuconazonium and rifampin
Isavuconazonium's FDA label of April 25, 2025 names rifampin in its contraindications section; the rifampin label PlainMeds reads does not name isavuconazonium. The isavuconazonium label: “Rifampin Contraindicate coadministration of all potent CYP3A4 inducers There is a 97% decrease in exposure of isavuconazole upon coadministration with rifampin.”
Check it at the source: the isavuconazonium FDA label on DailyMed (effective April 25, 2025, Astellas Pharma US, Inc.); the rifampin FDA label on DailyMed (effective February 11, 2026, Lupin Pharmaceuticals, Inc.).
What does the isavuconazonium label say about rifampin?
Isavuconazonium label, contraindicationsCoadministration of strong CYP3A4 inducers, such as rifampin, carbamazepine, St. John’s wort, or long acting barbiturates with CRESEMBA is contraindicated because strong CYP3A4 inducers can significantly decrease the plasma concentration of isavuconazole [see Drug Interactions ( 7 ) and Clinical Pharmacology ( 12.3 )].
Isavuconazonium label, drug interactionsRifampin Contraindicate coadministration of all potent CYP3A4 inducers There is a 97% decrease in exposure of isavuconazole upon coadministration with rifampin [see Clinical Pharmacology ( 12.3 )].
Isavuconazonium label, warnings and precautionsCoadministration of CRESEMBA with strong CYP3A4 inhibitors such as ketoconazole or high-dose ritonavir and strong CYP3A4 inducers such as rifampin, carbamazepine, St. John’s wort, or long acting barbiturates is contraindicated [see Contraindications ( 4 ) and Drug Interactions ( 7 )].
Source: FDA drug label (CRESEMBA), Astellas Pharma US, Inc., effective April 25, 2025 (SPL set 8f7f73b8-586a-4df0-935f-fecd4696c16c), via openFDA; the full label on DailyMed
What does the rifampin label say about isavuconazonium?
Rifampin's label (effective February 11, 2026) does not name isavuconazonium in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (rifampin), Lupin Pharmaceuticals, Inc., effective February 11, 2026 (SPL set b56004f0-f23d-47f6-80c7-39884fccbccc), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Isavuconazonium | Rifampin | |
|---|---|---|
| Labeled for | n/a | n/a |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $114.00 per capsule 186 mg capsule | $0.679 per capsule 300 mg capsule |
| Shortage now | No current entry | In shortage |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once