What the FDA labels say about taking them together
Ritonavir and toremifene
Toremifene's FDA label of November 13, 2024 names ritonavir in its drug interactions section; the ritonavir label PlainMeds reads does not name toremifene. The toremifene label: “The administration of FARESTON with agents that are strong CYP3A4 inhibitors increase the steady-state concentration in serum and should be avoided.”
Check it at the source: the ritonavir FDA label on DailyMed (effective July 23, 2026, AbbVie Inc.); the toremifene FDA label on DailyMed (effective November 13, 2024, Kyowa Kirin, Inc.).
What does the ritonavir label say about toremifene?
Ritonavir's label (effective July 23, 2026) does not name toremifene in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Norvir), AbbVie Inc., effective July 23, 2026 (SPL set 2849298e-de6e-47bb-8194-56e075b33fc3), via openFDA; the full label on DailyMed
What does the toremifene label say about ritonavir?
Toremifene label, drug interactionsThe administration of FARESTON with agents that are strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, clarithromycin, atazanavir, indinavir, nefazodone, nelfinavir, ritonavir, saquinavir, telithromycin, and voriconazole) increase the steady-state concentration in serum and should be avoided.
Source: FDA drug label (Fareston), Kyowa Kirin, Inc., effective November 13, 2024 (SPL set 2cab8dd1-3a10-48e6-86ce-0e5275ed49e5), 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
| Ritonavir | Toremifene | |
|---|---|---|
| Labeled for | HIV | Breast cancer |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.607 per tablet 100 mg tablet | $19.60 per tablet 60 mg tablet |
| Shortage now | A presentation being discontinued | 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