What the FDA labels say about taking them together
Bosentan and cobicistat
Cobicistat's FDA label of February 10, 2026 names bosentan in its drug interactions section; the bosentan label PlainMeds reads does not name cobicistat. The cobicistat label: “Initiation of bosentan in adult patients taking TYBOST coadministered with atazanavir or darunavir: In patients who have been receiving TYBOST coadministered with atazanavir or darunavir for at least 10 days, start …”
Check it at the source: the bosentan FDA label on DailyMed (effective November 17, 2025, Actelion Pharmaceuticals US, Inc.); the cobicistat FDA label on DailyMed (effective February 10, 2026, Gilead Sciences, Inc.).
What does the bosentan label say about cobicistat?
Bosentan's label (effective November 17, 2025) does not name cobicistat 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 cobicistat label say about bosentan?
Cobicistat label, drug interactionsConcomitant Drug Class/Drug Name: Endothelin Receptor Antagonists: bosentan; Potential Effect ↑ = Increase, ↓ = Decrease, ↔ = No change: ↑ bosentan ↓ cobicistat ↓ darunavir ↓ atazanavir; Clinical Comment: Initiation of bosentan in adult patients taking TYBOST coadministered with atazanavir or darunavir: In patients who have been receiving TYBOST coadministered with atazanavir or darunavir for at least 10 days, start bosentan at 62.5 mg once daily or every other day based upon individual tolerability. …
Source: FDA drug label (Tybost), Gilead Sciences, Inc., effective February 10, 2026 (SPL set 3784c35c-e87f-410c-900b-8fd6313c6010), 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 | Cobicistat | |
|---|---|---|
| Labeled for | Pulmonary arterial hypertension | HIV |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | n/a | n/a |
| 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