What the FDA labels say about taking them together
Rifampin and thiotepa
Thiotepa's FDA label of January 30, 2026 names rifampin in its drug interactions section; the rifampin label PlainMeds reads does not name thiotepa. The thiotepa label: “Avoid co-administration of strong CYP3A4 inhibitors and strong CYP3A4 inducers with TEPADINA due to the potential effects on efficacy and toxicity.”
Check it at the source: the rifampin FDA label on DailyMed (effective February 11, 2026, Lupin Pharmaceuticals, Inc.); the thiotepa FDA label on DailyMed (effective January 30, 2026, Amneal Pharmaceuticals LLC).
What does the rifampin label say about thiotepa?
Rifampin's label (effective February 11, 2026) does not name thiotepa 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
What does the thiotepa label say about rifampin?
Thiotepa label, drug interactionsAvoid co-administration of strong CYP3A4 inhibitors (e.g., itraconazole, clarithromycin, ritonavir) and strong CYP3A4 inducers (e.g., rifampin, phenytoin) with TEPADINA due to the potential effects on efficacy and toxicity [see Clinical Pharmacology ( 12.3 ) ].
Source: FDA drug label (TEPADINA), NDA208264 (Adienne Sa), as published by Amneal Pharmaceuticals LLC, effective January 30, 2026 (SPL set 559e353c-2dc0-16ba-e054-00144ff8d46c), 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
| Rifampin | Thiotepa | |
|---|---|---|
| Labeled for | n/a | Organ transplant rejection |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $0.679 per capsule 300 mg capsule | n/a |
| Shortage now | In shortage | No current entry |
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