What the FDA labels say about taking them together
Rifabutin and ritonavir
Rifabutin's FDA label of September 1, 2026 names ritonavir in its drug interactions section, and ritonavir's label names rifabutin too. The ritonavir label: “Dosage reduction of rifabutin by at least three-quarters of the usual dose of 300 mg per day is recommended. Further dosage reduction may be necessary.”
Check it at the source: the rifabutin FDA label on DailyMed (effective September 1, 2026, REMEDYREPACK INC.); the ritonavir FDA label on DailyMed (effective July 23, 2026, AbbVie Inc.).
What does the rifabutin label say about ritonavir?
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
What does the ritonavir label say about rifabutin?
Ritonavir label, drug interactionsConcomitant Drug Class/Drug Name: Antimycobacterial: rifabutin; Effect on Concentration of Ritonavir or Concomitant Drug: ↑ rifabutin and rifabutin metabolite; Clinical Comment: Dosage reduction of rifabutin by at least three-quarters of the usual dose of 300 mg per day is recommended (e.g., 150 mg every other day or three times a week). Further dosage reduction may be necessary.
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
| Rifabutin | Ritonavir | |
|---|---|---|
| Labeled for | n/a | HIV |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $8.14 per capsule 150 mg capsule | $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