What the FDA labels say about taking them together
Sirolimus and temsirolimus
Temsirolimus's FDA label of December 26, 2025 names sirolimus in its drug interactions section; the sirolimus labels PlainMeds reads (4) do 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 sirolimus FDA label on DailyMed (effective January 28, 2026, Glenmark Pharmaceuticals Inc., USA); the temsirolimus FDA label on DailyMed (effective December 26, 2025, Wyeth Pharmaceuticals LLC, a subsidiary of Pfizer Inc.).
What does the sirolimus label say about temsirolimus?
Sirolimus's label (effective January 28, 2026) and its 3 other brand-application labels do 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 (sirolimus), Glenmark Pharmaceuticals Inc., USA, effective January 28, 2026 (SPL set 57fb4d90-3ccb-4a69-af1e-53be83f7a504), via openFDA; the full label on DailyMed
What does the temsirolimus label say about sirolimus?
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 precautionsTORISEL should be used with caution in persons with known hypersensitivity to temsirolimus or its metabolites (including sirolimus), polysorbate 80, or to any other component (including the excipients) of TORISEL.
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
| Sirolimus | Temsirolimus | |
|---|---|---|
| Labeled for | Organ transplant rejection | n/a |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $0.723 per tablet 1 mg tablet | n/a |
| Shortage now | No current entry | 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