What the FDA labels say about taking them together
Estrogens conjugated and ritonavir
Estrogens conjugated's FDA label of June 4, 2026 names ritonavir in its drug interactions section; the ritonavir label PlainMeds reads does not name estrogens conjugated. The estrogens conjugated label: “Inhibitors of CYP3A4, such as erythromycin, clarithromycin, ketoconazole, itraconazole, ritonavir and grapefruit juice, may increase plasma concentrations of estrogens and may result in side effects.”
Check it at the source: the estrogens conjugated FDA label on DailyMed (effective June 4, 2026, Wyeth Pharmaceuticals LLC, a subsidiary of Pfizer Inc.); the ritonavir FDA label on DailyMed (effective July 23, 2026, AbbVie Inc.).
What does the estrogens conjugated label say about ritonavir?
Estrogens conjugated 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 side effects.
Source: FDA drug label (Premarin), Wyeth Pharmaceuticals LLC, a subsidiary of Pfizer Inc., effective June 4, 2026 (SPL set 258e1602-a3cf-4ccc-ca80-73dbbfb812ff), via openFDA; the full label on DailyMed
What does the ritonavir label say about estrogens conjugated?
Ritonavir's label (effective July 23, 2026) does not name estrogens conjugated 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
| Estrogens conjugated | Ritonavir | |
|---|---|---|
| Labeled for | Menopause symptoms, Breast cancer, Osteoporosis | HIV |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $5.47 per tablet 0.625 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