What the FDA labels say about taking them together
Rifampin and temsirolimus
Temsirolimus's FDA label of December 26, 2025 names rifampin in its drug interactions section; the rifampin label PlainMeds reads does not name temsirolimus. The temsirolimus label: “Agents Inducing CYP3A Metabolism Co-administration of TORISEL with rifampin, a potent CYP3A4/5 inducer, had no significant effect on temsirolimus C max (maximum concentration) and AUC after intravenous administration …”
Check it at the source: the rifampin FDA label on DailyMed (effective February 11, 2026, Lupin Pharmaceuticals, Inc.); the temsirolimus FDA label on DailyMed (effective December 26, 2025, Wyeth Pharmaceuticals LLC, a subsidiary of Pfizer Inc.).
What does the rifampin label say about temsirolimus?
Rifampin's label (effective February 11, 2026) does not name temsirolimus 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 temsirolimus label say about rifampin?
Temsirolimus label, drug interactionsAgents Inducing CYP3A Metabolism Co-administration of TORISEL with rifampin, a potent CYP3A4/5 inducer, had no significant effect on temsirolimus C max (maximum concentration) and AUC (area under the concentration versus the time curve) after intravenous administration, but decreased sirolimus C max by 65% and AUC by 56% compared to TORISEL treatment alone.
Temsirolimus label, warnings and precautionsInducers or Inhibitors of CYP3A Metabolism Agents Inducing CYP3A Metabolism: Strong inducers of CYP3A4/5 such as dexamethasone, carbamazepine, phenytoin, phenobarbital, rifampin, rifabutin, and rifampacin may decrease exposure of the active metabolite, sirolimus.
Source: FDA drug label (Torisel), NDA022088 (Pf Prism Cv), as published by Wyeth Pharmaceuticals LLC, a subsidiary of Pfizer Inc., effective December 26, 2025 (SPL set 95b7dc92-2180-42f1-8699-3c28f609e674), 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 | Temsirolimus | |
|---|---|---|
| Labeled for | n/a | n/a |
| Boxed warning | No | No |
| 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