What the FDA labels say about taking them together
Rifabutin and sofosbuvir
Rifabutin's FDA label of September 1, 2026 names sofosbuvir in its drug interactions section, and sofosbuvir's label names rifabutin too. The rifabutin label: “Co-administration of rifabutin with sofosbuvir (alone or in combination) is not recommended.”
Check it at the source: the rifabutin FDA label on DailyMed (effective September 1, 2026, REMEDYREPACK INC.); the sofosbuvir FDA label on DailyMed (effective December 26, 2024, Gilead Sciences, Inc.).
What does the rifabutin label say about sofosbuvir?
Rifabutin label, drug interactionsCo-administered drug: Sofosbuvir; Dosing regimen of co-administered drug: 400 mg on day 1 and day 21; Dosing regimen of rifabutin: 300 mg daily on day 10 to day 29; Study population (n): Healthy subjects (20); Effect on rifabutin: ND; Effect on co-administered drug: 36% ↓ in C max and 24% ↓ AUC; Recommendation: Co-administration of rifabutin with sofosbuvir (alone or in combination) is not recommended.
Rifabutin label, warningsCo-administration with antiretroviral drugs metabolized by CYP3A, including but not limited to products containing bictegravir, elvitegravir, oral rilpivirine, or doravirine and anti-HCV drugs including but not limited to sofosbuvir (alone or in combination) may decrease plasma concentrations of those drugs, which may lead to loss of virologic response and possible development of resistance.
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 sofosbuvir label say about rifabutin?
Sofosbuvir label, drug interactionsConcomitant Drug Class/Drug Name: Antimycobacterials: Rifabutin rifampin rifapentine; Effect on Concentration ↓ = decrease.: ↓ sofosbuvir ↓ GS-331007; Clinical Comment: Coadministration of SOVALDI with rifabutin or rifapentine is expected to decrease the concentration of sofosbuvir, leading to reduced therapeutic effect of SOVALDI. Coadministration is not recommended. Coadministration of SOVALDI with rifampin, an intestinal P-gp inducer, is not recommended [see].
Source: FDA drug label (Sovaldi), Gilead Sciences, Inc., effective December 26, 2024 (SPL set 80beab2c-396e-4a37-a4dc-40fdb62859cf), 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 | Sofosbuvir | |
|---|---|---|
| Labeled for | n/a | Hepatitis C |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $8.14 per capsule 150 mg capsule | n/a |
| 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