What the FDA labels say about taking them together
Fosamprenavir and ritonavir
Fosamprenavir's FDA label of September 15, 2023 names ritonavir in its contraindications section, and ritonavir's label names fosamprenavir too. The fosamprenavir label: “The list of contraindicated drugs applies to the use of fosamprenavir with or without ritonavir, unless otherwise indicated.”
Check it at the source: the fosamprenavir FDA label on DailyMed (effective September 15, 2023, Mylan Pharmaceuticals Inc.); the ritonavir FDA label on DailyMed (effective July 23, 2026, AbbVie Inc.).
What does the fosamprenavir label say about ritonavir?
Fosamprenavir label, contraindicationsThe list of contraindicated drugs applies to the use of fosamprenavir with or without ritonavir, unless otherwise indicated.
Fosamprenavir label, drug interactionsCoadministration of fosamprenavir or fosamprenavir and ritonavir may result in clinically significant interactions with drugs metabolized by CYP3A4.
Fosamprenavir label, warnings and precautionsThe concomitant use of fosamprenavir with ritonavir and certain other drugs may result in known or potentially significant drug interactions.
Source: FDA drug label (Fosamprenavir Calcium), Mylan Pharmaceuticals Inc., effective September 15, 2023 (SPL set 3a1424d8-844c-4e24-9ebd-b2c2b61b61a3), via openFDA; the full label on DailyMed
What does the ritonavir label say about fosamprenavir?
Ritonavir label, drug interactionsConcomitant Drug Class/Drug Name: HIV-1 Protease Inhibitor: atazanavir darunavir fosamprenavir; Effect on Concentration of Ritonavir or Concomitant Drug: ↑ amprenavir ↑ atazanavir ↑ darunavir; Clinical Comment: See the complete prescribing information for fosamprenavir, atazanavir, darunavir for details on co-administration with ritonavir.
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
| Fosamprenavir | Ritonavir | |
|---|---|---|
| Labeled for | HIV | HIV |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | n/a | $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