What the FDA labels say about taking them together
Estradiol and ritonavir
Estradiol's FDA label of April 3, 2024 names ritonavir in its drug interactions section; the ritonavir label PlainMeds reads does not name estradiol. The estradiol label: “Inhibitors of CYP3A4, such as erythromycin, clarithromycin, ketoconazole, itraconazole, ritonavir, and grapefruit juice, may increase plasma concentrations of estrogens and result in adverse reactions.”
Check it at the source: the estradiol FDA label on DailyMed (effective April 3, 2024, Amneal Pharmaceuticals LLC); the ritonavir FDA label on DailyMed (effective July 23, 2026, AbbVie Inc.).
What does the estradiol label say about ritonavir?
Estradiol label, drug interactionsInhibitors of CYP3A4 such as erythromycin, clarithromycin, ketoconazole, itraconazole, ritonavir and grapefruit juice may increase plasma concentrations of estrogens and may result in adverse reactions.
Source: FDA drug label (Divigel, NDA022038), Vertical Pharmaceuticals, LLC, effective February 27, 2026 (SPL set 59e610dc-883e-4f07-9ec6-a5841b0bf9fb), via openFDA
Source: FDA drug label (YUVAFEM), Amneal Pharmaceuticals LLC, effective April 3, 2024 (SPL set 30c7f6ba-7a9e-4853-b3e4-e00a46560224), via openFDA; the full label on DailyMed
What does the ritonavir label say about estradiol?
Ritonavir's label (effective July 23, 2026) does not name estradiol 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.
Which combination products and biosimilars carry the same label text?
Their labels quote the same sentences for their ingredient; each has its own page with its own label dates.
Both medicines on the record
| Estradiol | Ritonavir | |
|---|---|---|
| Labeled for | Menopause symptoms, Breast cancer, Osteoporosis | HIV |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.0635 per tablet 1 mg tablet | $0.607 per tablet 100 mg tablet |
| Shortage now | No current entry | 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