What the FDA labels say about taking them together
Rifabutin and zidovudine
Rifabutin's FDA label of September 1, 2026 names zidovudine in its drug interactions section; the zidovudine labels PlainMeds reads (3) do not name rifabutin. The rifabutin label: “Reduce rifabutin dose by at least 75% when given with lopinavir/ritonavir combination. Monitor closely for adverse reactions. Reduce rifabutin dosage further, as needed.”
Check it at the source: the rifabutin FDA label on DailyMed (effective September 1, 2026, REMEDYREPACK INC.); the zidovudine FDA label on DailyMed (effective February 10, 2025, Aurobindo Pharma Limited).
What does the rifabutin label say about zidovudine?
Rifabutin label, drug interactionsCo-administered drug: Lopinavir/ ritonavir; Dosing regimen of co-administered drug: 400/100 mg twice a day for 20 days; Dosing regimen of rifabutin: 150 mg once a day for 10 days; Study population (n): Healthy subjects (14); Effect on rifabutin: ↑ AUC by 203% also taking zidovudine 500 mg once a day ↓ C max by 112%; Effect on co-administered drug: ↔; Recommendation: Reduce rifabutin dose by at least 75% (to a maximum 150 mg every other day or three times per week) when given with lopinavir/ritonavir combination. Monitor closely for adverse reactions. Reduce rifabutin dosage further, as needed.
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 zidovudine label say about rifabutin?
Zidovudine's label (effective February 10, 2025) and its 2 other brand-application labels do not name rifabutin in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Zidovudine), Aurobindo Pharma Limited, effective February 10, 2025 (SPL set 51abd2ce-6be1-412d-b806-5f24935ac5e3), 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 | Zidovudine | |
|---|---|---|
| Labeled for | n/a | HIV |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $8.14 per capsule 150 mg capsule | $0.464 per tablet 300 mg tablet |
| 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