What the FDA labels say about taking them together
Enzalutamide and rifampin
Enzalutamide's FDA label of July 28, 2026 names rifampin in its drug interactions section; the rifampin label PlainMeds reads does not name enzalutamide. The enzalutamide label: “Drugs that Induce CYP3A4 Co-administration of rifampin decreased the composite AUC of enzalutamide plus N-desmethyl enzalutamide by 37%.”
Check it at the source: the enzalutamide FDA label on DailyMed (effective July 28, 2026, Astellas Pharma US, Inc.); the rifampin FDA label on DailyMed (effective February 11, 2026, Lupin Pharmaceuticals, Inc.).
What does the enzalutamide label say about rifampin?
Enzalutamide label, drug interactionsStrong CYP3A4 Inducers The coadministration of XTANDI with rifampin (a strong CYP3A4 inducer and a moderate CYP2C8 inducer) decreases plasma concentrations of enzalutamide plus N-desmethyl enzalutamide, which may decrease the efficacy of XTANDI.
Xtandi label (Astellas Pharma US, Inc., May 25, 2021), drug interactionsDrugs that Induce CYP3A4 Co-administration of rifampin (strong CYP3A4 inducer and moderate CYP2C8 inducer) decreased the composite AUC of enzalutamide plus N-desmethyl enzalutamide by 37%.
Source: FDA drug label (Xtandi, NDA213674), Astellas Pharma US, Inc., effective May 25, 2021 (SPL set 381cd215-78c9-4208-8595-7ae7a279b236), via openFDA
Source: FDA drug label (Xtandi), Astellas Pharma US, Inc., effective July 28, 2026 (SPL set b129fdc9-1d8e-425c-a5a9-8a2ed36dfbdf), via openFDA; the full label on DailyMed
What does the rifampin label say about enzalutamide?
Rifampin's label (effective February 11, 2026) does not name enzalutamide 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
| Enzalutamide | Rifampin | |
|---|---|---|
| Labeled for | Prostate cancer | n/a |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | n/a | $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