What the FDA labels say about taking them together
Atazanavir and bosentan
Atazanavir's FDA label of August 6, 2025 names bosentan in its drug interactions section; the bosentan label PlainMeds reads does not name atazanavir. The atazanavir label: “Coadministration of bosentan and atazanavir without ritonavir is not recommended. For adult patients who have been receiving atazanavir with ritonavir for at least 10 days, start bosentan at 62.5 mg once daily or every …”
Check it at the source: the atazanavir FDA label on DailyMed (effective August 6, 2025, Aurobindo Pharma Limited); the bosentan FDA label on DailyMed (effective November 17, 2025, Actelion Pharmaceuticals US, Inc.).
What does the atazanavir label say about bosentan?
Atazanavir label, drug interactionsConcomitant Drug Class/Specific Drugs: Endothelin receptor antagonists: bosentan; Effect on Concentration of Atazanavir or Concomitant Drug: Atazanavir ↓ atazanavir Atazanavir with ritonavir ↑ bosentan; Clinical Comment: Coadministration of bosentan and atazanavir without ritonavir is not recommended. For adult patients who have been receiving atazanavir with ritonavir for at least 10 days, start bosentan at 62.5 mg once daily or every other day based on individual tolerability. For adult patients who have been receiving bosentan, discontinue bosentan at least 36 hours before starting atazanavir with ritonavir. …
Source: FDA drug label (Reyataz, NDA021567), E.R. Squibb & Sons, L.L.C., effective December 5, 2024 (SPL set 165cff62-b284-4a27-a65d-9ec8a5bfcdd8), via openFDA
Source: FDA drug label (Atazanavir Sulfate), Aurobindo Pharma Limited, effective August 6, 2025 (SPL set 7fbea274-d6b5-4faa-bbf0-05fefab42114), via openFDA; the full label on DailyMed
What does the bosentan label say about atazanavir?
Bosentan's label (effective November 17, 2025) does not name atazanavir 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
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
| Atazanavir | Bosentan | |
|---|---|---|
| Labeled for | HIV | Pulmonary arterial hypertension |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $2.23 per capsule 300 mg capsule | 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