What the FDA labels say about taking them together
Atazanavir and rifabutin
Atazanavir's FDA label of August 6, 2025 names rifabutin in its drug interactions section, and rifabutin's label names atazanavir too. The rifabutin label: “A reduction in the dose of rifabutin is recommended. Increased monitoring for adverse reactions is warranted.”
Check it at the source: the atazanavir FDA label on DailyMed (effective August 6, 2025, Aurobindo Pharma Limited); the rifabutin FDA label on DailyMed (effective September 1, 2026, REMEDYREPACK INC.).
What does the atazanavir label say about rifabutin?
Atazanavir label, drug interactionsConcomitant Drug Class/Specific Drugs: rifabutin; Effect on Concentration of Atazanavir or Concomitant Drug: ↑ rifabutin; Clinical Comment: A rifabutin dose reduction of up to 75% (e.g., 150 mg every other day or 3 times per week) is recommended. Increased monitoring for rifabutin-associated adverse reactions including neutropenia is warranted.
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 rifabutin label say about atazanavir?
Rifabutin label, drug interactionsCo-administered drug: Atazanavir/Ritonavir; Dosing regimen of co-administered drug: 300/100 mg once daily; Dosing regimen of rifabutin: 150 mg twice weekly; Study population (n): Healthy adult subjects; Effect on rifabutin: 48% ↑ in AUC, 149% ↑ C max of rifabutin. 990% ↑ in AUC, 677% ↑ C max of 25-O-desacetyl-rifabutin.; Effect on co-administered drug: No significant change in pharmacokinetics.; Recommendation: A reduction in the dose of rifabutin (to 150 mg every other day or 3 times a week) is recommended. Increased monitoring for adverse reactions is warranted.
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
| Atazanavir | Rifabutin | |
|---|---|---|
| Labeled for | HIV | n/a |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $2.23 per capsule 300 mg capsule | $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