What the FDA labels say about taking them together
Bosentan and fosamprenavir
Fosamprenavir's FDA label of September 15, 2023 names bosentan in its drug interactions section; the bosentan label PlainMeds reads does not name fosamprenavir.
Check it at the source: the bosentan FDA label on DailyMed (effective November 17, 2025, Actelion Pharmaceuticals US, Inc.); the fosamprenavir FDA label on DailyMed (effective September 15, 2023, Mylan Pharmaceuticals Inc.).
What does the bosentan label say about fosamprenavir?
Bosentan's label (effective November 17, 2025) does not name fosamprenavir in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Tracleer), Actelion Pharmaceuticals US, Inc., effective November 17, 2025 (SPL set 749e42fb-2fe0-45dd-9268-b43bb3f4081c), via openFDA; the full label on DailyMed
What does the fosamprenavir label say about bosentan?
Fosamprenavir label, drug interactionsConcomitant Drug Class/Drug Name: Endothelin-receptor antagonist: Bosentan; Effect on Concentration of Amprenavir or Concomitant Drug: ↑ Bosentan; Clinical Comment: Coadministration of bosentan in patients on fosamprenavir: In patients who have been receiving fosamprenavir for at least 10 days, start bosentan at 62.5 mg once daily or every other day based upon individual tolerability. Coadministration of fosamprenavir in patients on bosentan: Discontinue use of bosentan at least 36 hours prior to initiation of fosamprenavir. After at least 10 days following the initiation of fosamprenavir, resume bosentan at 62.5 mg once daily or every other day based upon individual tolerability.
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
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
| Bosentan | Fosamprenavir | |
|---|---|---|
| Labeled for | Pulmonary arterial hypertension | HIV |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | n/a | n/a |
| Shortage now | No current entry | 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