What the FDA labels say about taking them together
Palbociclib and ritonavir
Palbociclib's FDA label of July 2, 2026 names ritonavir in its drug interactions section; the ritonavir label PlainMeds reads does not name palbociclib. The palbociclib label: “Avoid concomitant use of strong CYP3A inhibitors.”
Check it at the source: the palbociclib FDA label on DailyMed (effective July 2, 2026, Pfizer Laboratories Div Pfizer Inc); the ritonavir FDA label on DailyMed (effective July 23, 2026, AbbVie Inc.).
What does the palbociclib label say about ritonavir?
Palbociclib label, drug interactionsAvoid concomitant use of strong CYP3A inhibitors (e.g., clarithromycin, indinavir, itraconazole, ketoconazole, lopinavir/ritonavir, nefazodone, nelfinavir, posaconazole, ritonavir, saquinavir, telaprevir, telithromycin, and voriconazole).
Source: FDA drug label (Ibrance), Pfizer Laboratories Div Pfizer Inc, effective July 2, 2026 (SPL set fecbdd7d-b729-41b5-9872-231b8fe104ce), via openFDA; the full label on DailyMed
What does the ritonavir label say about palbociclib?
Ritonavir's label (effective July 23, 2026) does not name palbociclib 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
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
| Palbociclib | Ritonavir | |
|---|---|---|
| Labeled for | Breast cancer | HIV |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | n/a | $0.607 per tablet 100 mg tablet |
| Shortage now | A presentation being discontinued | A presentation being discontinued |
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