What the FDA labels say about taking them together
Darunavir and rifabutin
Darunavir's FDA label of August 29, 2025 names rifabutin in its drug interactions section, and rifabutin's label names darunavir too. The darunavir label: “Dose reduction of rifabutin by at least 75% of the usual dose (300 mg once daily) is recommended. Increased monitoring for adverse events is warranted in patients receiving this combination and further dose reduction of …”
Check it at the source: the darunavir FDA label on DailyMed (effective August 29, 2025, Janssen Products LP); the rifabutin FDA label on DailyMed (effective September 1, 2026, REMEDYREPACK INC.).
What does the darunavir label say about rifabutin?
Darunavir label, drug interactionsConcomitant Drug Class Drug Name Examples: rifabutin (The reference regimen for rifabutin was 300 mg once daily.); Effect on Concentration of Darunavir Or Concomitant Drug: ↑ darunavir ↑ rifabutin ↑ 25- O -desacetylrifabutin; Clinical Comment: Dose reduction of rifabutin by at least 75% of the usual dose (300 mg once daily) is recommended (i.e., a maximum dose of 150 mg every other day). Increased monitoring for adverse events is warranted in patients receiving this combination and further dose reduction of rifabutin may be necessary.
Source: FDA drug label (PREZISTA), Janssen Products LP, effective August 29, 2025 (SPL set 814301f9-c990-46a5-b481-2879a521a16f), via openFDA; the full label on DailyMed
What does the rifabutin label say about darunavir?
Rifabutin label, drug interactionsDarunavir/Ritonavir 600/100 mg twice a day for 12 days 150 mg every other day for 12 days Healthy HIV- negative adults No significant change in rifabutin pharmacokinetics.
Source: FDA drug label (Rifabutin), NDA050689 (Pfizer), as published by REMEDYREPACK INC., effective September 1, 2026 (SPL set 25a60937-cbbe-4a50-994f-2ce15203f589), 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
| Darunavir | Rifabutin | |
|---|---|---|
| Labeled for | HIV | n/a |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $1.16 per tablet 600 mg tablet | $8.14 per capsule 150 mg capsule |
| 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